404 error when editing or posting a new article

Question

I'm having an issue with a 404 error that appears after creating a new article entry, or editing a template.

I recently upgraded my website to the latest version of ExpressionEngine, following the official guide step by step. Before the upgrade this problem was still present but instead of getting a permission denied or a 404 I got a message pop-up about disallowed characters. Except after the upgrade, the problem has changed.

I have a large article write-up I have spent some time on, and when I went to submit the article the article I used to get a disallowed character alert, despite not using any disallowed characters (as far as I was aware). After my upgrade to the latest ExpressionEngine, I now receive a 404 error (I disabled CloudFlare to get a better error).

Similarly, there have been a few changes to my template, introducing some new items and changes to the CSS theme. However, when I edit a template or even just save it without making changes, I'm redirected to my website 404 page.

Excluding the update the only change I have made of significance is a change to my .htaccess file to redirect any visitors without a subdomain to the www subdomain.

<IfModule mod_rewrite.c>
    RewriteEngine On
    RewriteBase /

    # Replaces all non-subdomain connections with a www subdomain.
    RewriteCond %{HTTP_HOST} ^bowl-of-soup\.co.uk$ [NC]
    RewriteRule ^(.*)$ http://www.bowl-of-soup.co.uk/$1 [R=301,L]


    # Removes index.php from ExpressionEngine URLs
    RewriteCond %{THE_REQUEST} ^GET.*index\.php [NC]
    RewriteCond %{REQUEST_URI} !/system/.* [NC]
    RewriteRule (.*?)index\.php/*(.*) /$1$2 [R=301,NE,L]

    # Directs all EE web requests through the site index file
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteCond %{REQUEST_FILENAME} !-d
    RewriteRule ^(.*)$ /index.php/$1 [L]
</IfModule>

Long story short I am getting 404 errors when I edit my template or my articles, and before that I was getting disallowed keys error. Does anyone know what could be causing this problem?

Edit (6/12/2014)

I opened up my normalize.css file and without changing anything submitted it and it triggered a 404. However, I ran the CSS through a CSS clean-up tool and saved it again, this time it passed through, and any saves and changes made are accepted by the system.

I've been trying to insert characters that were unique to the CSS before I cleaned it up, but none of them seem to trigger the 404. I'm not sure this is a .htaccess issue any more, as I was getting Disallowed key characters before. Is there a page associated with this error? I suspect during the upgrade whatever code displays that error has been corrupted. Otherwise, the disallowed key characters is causing my issues.

For reference:

Adding this unminified CSS (normalize github) will trigger a 404 (possible disallowed key characters)

I removed the comments and this version (my website cleaned version) was accepted by my system.

Answer 1

I agree that someone will need CP / FTP access to really help you, but it sounds like you're having issues with .htaccess and I would start with updating that to the following. It's a tried and true file that I have used for years on all kinds of builds:

# Apache configuration file
# httpd.apache.org/docs/2.2/mod/quickreference.html

# Note .htaccess files are an overhead, this logic should be in your Apache
# config if possible: httpd.apache.org/docs/2.2/howto/htaccess.html

# Techniques in here adapted from all over, including:
#   Kroc Camen: camendesign.com/.htaccess
#   perishablepress.com/press/2006/01/10/stupid-htaccess-tricks/
#   Sample .htaccess file of CMS MODx: modxcms.com


# ----------------------------------------------------------------------
# Better website experience for IE users
# ----------------------------------------------------------------------

# Force the latest IE version, in various cases when it may fall back to IE7 mode
#  github.com/rails/rails/commit/123eb25#commitcomment-118920
# Use ChromeFrame if it's installed for a better experience for the poor IE folk

<IfModule mod_headers.c>
  Header set X-UA-Compatible "IE=Edge,chrome=1"
  # mod_headers can't match by content-type, but we don't want to send this header on *everything*...
  <FilesMatch "\.(js|css|gif|png|jpe?g|pdf|xml|oga|ogg|m4a|ogv|mp4|m4v|webm|svg|svgz|eot|ttf|otf|woff|ico|webp|appcache|manifest|htc|crx|oex|xpi|safariextz|vcf)$" >
    Header unset X-UA-Compatible
  </FilesMatch>
</IfModule>


# ----------------------------------------------------------------------
# Cross-domain AJAX requests
# ----------------------------------------------------------------------

# Serve cross-domain Ajax requests, disabled by default.
# enable-cors.org
# code.google.com/p/html5security/wiki/CrossOriginRequestSecurity

#  <IfModule mod_headers.c>
#    Header set Access-Control-Allow-Origin "*"
#  </IfModule>


# ----------------------------------------------------------------------
# CORS-enabled images (@crossorigin)
# ----------------------------------------------------------------------

# Send CORS headers if browsers request them; enabled by default for images.
# developer.mozilla.org/en/CORS_Enabled_Image
# blog.chromium.org/2011/07/using-cross-domain-images-in-webgl-and.html
# hacks.mozilla.org/2011/11/using-cors-to-load-webgl-textures-from-cross-domain-images/
# wiki.mozilla.org/Security/Reviews/crossoriginAttribute

<IfModule mod_setenvif.c>
  <IfModule mod_headers.c>
    # mod_headers, y u no match by Content-Type?!
    <FilesMatch "\.(gif|png|jpe?g|svg|svgz|ico|webp)$">
      SetEnvIf Origin ":" IS_CORS
      Header set Access-Control-Allow-Origin "*" env=IS_CORS
    </FilesMatch>
  </IfModule>
</IfModule>


# ----------------------------------------------------------------------
# Webfont access
# ----------------------------------------------------------------------

# Allow access from all domains for webfonts.
# Alternatively you could only whitelist your
# subdomains like "subdomain.example.com".

<IfModule mod_headers.c>
  <FilesMatch "\.(ttf|ttc|otf|eot|woff|font.css)$">
    Header set Access-Control-Allow-Origin "*"
  </FilesMatch>
</IfModule>


# ----------------------------------------------------------------------
# Proper MIME type for all files
# ----------------------------------------------------------------------

# JavaScript
#   Normalize to standard type (it's sniffed in IE anyways)
#   tools.ietf.org/html/rfc4329#section-7.2
AddType application/javascript         js jsonp
AddType application/json               json

# Audio
AddType audio/ogg                      oga ogg
AddType audio/mp4                      m4a f4a f4b

# Video
AddType video/ogg                      ogv
AddType video/mp4                      mp4 m4v f4v f4p
AddType video/webm                     webm
AddType video/x-flv                    flv

# SVG
#   Required for svg webfonts on iPad
#   twitter.com/FontSquirrel/status/14855840545
AddType     image/svg+xml              svg svgz
AddEncoding gzip                       svgz

# Webfonts
AddType application/vnd.ms-fontobject  eot
AddType application/x-font-ttf         ttf ttc
AddType font/opentype                  otf
AddType application/x-font-woff        woff

# Assorted types
AddType image/x-icon                        ico
AddType image/webp                          webp
AddType text/cache-manifest                 appcache manifest
AddType text/x-component                    htc
AddType application/xml                     rss atom xml rdf
AddType application/x-chrome-extension      crx
AddType application/x-opera-extension       oex
AddType application/x-xpinstall             xpi
AddType application/octet-stream            safariextz
AddType application/x-web-app-manifest+json webapp
AddType text/x-vcard                        vcf
AddType application/x-shockwave-flash       swf
AddType text/vtt                            vtt


# ----------------------------------------------------------------------
# Allow concatenation from within specific js and css files
# ----------------------------------------------------------------------

# e.g. Inside of script.combined.js you could have
#   <!--#include file="libs/jquery-1.5.0.min.js" -->
#   <!--#include file="plugins/jquery.idletimer.js" -->
# and they would be included into this single file.

# This is not in use in the boilerplate as it stands. You may
# choose to use this technique if you do not have a build process.

#<FilesMatch "\.combined\.js$">
#  Options +Includes
#  AddOutputFilterByType INCLUDES application/javascript application/json
#  SetOutputFilter INCLUDES
#</FilesMatch>

#<FilesMatch "\.combined\.css$">
#  Options +Includes
#  AddOutputFilterByType INCLUDES text/css
#  SetOutputFilter INCLUDES
#</FilesMatch>


# ----------------------------------------------------------------------
# Gzip compression
# ----------------------------------------------------------------------

<IfModule mod_deflate.c>

  # Force deflate for mangled headers developer.yahoo.com/blogs/ydn/posts/2010/12/pushing-beyond-gzipping/
  <IfModule mod_setenvif.c>
    <IfModule mod_headers.c>
      SetEnvIfNoCase ^(Accept-EncodXng|X-cept-Encoding|X{15}|~{15}|-{15})$ ^((gzip|deflate)\s*,?\s*)+|[X~-]{4,13}$ HAVE_Accept-Encoding
      RequestHeader append Accept-Encoding "gzip,deflate" env=HAVE_Accept-Encoding
    </IfModule>
  </IfModule>

  # Compress all output labeled with one of the following MIME-types
  <IfModule mod_filter.c>
    AddOutputFilterByType DEFLATE application/atom+xml \
                                  application/javascript \
                                  application/json \
                                  application/rss+xml \
                                  application/vnd.ms-fontobject \
                                  application/x-font-ttf \
                                  application/xhtml+xml \
                                  application/xml \
                                  font/opentype \
                                  image/svg+xml \
                                  image/x-icon \
                                  text/css \
                                  text/html \
                                  text/plain \
                                  text/x-component \
                                  text/xml
  </IfModule>

</IfModule>


# ----------------------------------------------------------------------
# Expires headers (for better cache control)
# ----------------------------------------------------------------------

# These are pretty far-future expires headers.
# They assume you control versioning with filename-based cache busting
# Additionally, consider that outdated proxies may miscache
#   www.stevesouders.com/blog/2008/08/23/revving-filenames-dont-use-querystring/

# If you don't use filenames to version, lower the CSS and JS to something like
# "access plus 1 week".

<IfModule mod_expires.c>
  ExpiresActive on

# Perhaps better to whitelist expires rules? Perhaps.
  ExpiresDefault                          "access plus 1 month"

# cache.appcache needs re-requests in FF 3.6 (thanks Remy ~Introducing HTML5)
  ExpiresByType text/cache-manifest       "access plus 0 seconds"

# Your document html
  ExpiresByType text/html                 "access plus 0 seconds"

# Data
  ExpiresByType text/xml                  "access plus 0 seconds"
  ExpiresByType application/xml           "access plus 0 seconds"
  ExpiresByType application/json          "access plus 0 seconds"

# Feed
  ExpiresByType application/rss+xml       "access plus 1 hour"
  ExpiresByType application/atom+xml      "access plus 1 hour"

# Favicon (cannot be renamed)
  ExpiresByType image/x-icon              "access plus 1 week"

# Media: images, video, audio
  ExpiresByType image/gif                 "access plus 1 month"
  ExpiresByType image/png                 "access plus 1 month"
  ExpiresByType image/jpeg                "access plus 1 month"
  ExpiresByType video/ogg                 "access plus 1 month"
  ExpiresByType audio/ogg                 "access plus 1 month"
  ExpiresByType video/mp4                 "access plus 1 month"
  ExpiresByType video/webm                "access plus 1 month"

# HTC files  (css3pie)
  ExpiresByType text/x-component          "access plus 1 month"

# Webfonts
  ExpiresByType application/x-font-ttf    "access plus 1 month"
  ExpiresByType font/opentype             "access plus 1 month"
  ExpiresByType application/x-font-woff   "access plus 1 month"
  ExpiresByType image/svg+xml             "access plus 1 month"
  ExpiresByType application/vnd.ms-fontobject "access plus 1 month"

# CSS and JavaScript
  ExpiresByType text/css                  "access plus 1 year"
  ExpiresByType application/javascript    "access plus 1 year"

</IfModule>


# ----------------------------------------------------------------------
# Prevent mobile network providers from modifying your site
# ----------------------------------------------------------------------

# The following header prevents modification of your code over 3G on some
# European providers.
# This is the official 'bypass' suggested by O2 in the UK.

# <IfModule mod_headers.c>
# Header set Cache-Control "no-transform"
# </IfModule>


# ----------------------------------------------------------------------
# ETag removal
# ----------------------------------------------------------------------

# FileETag None is not enough for every server.
<IfModule mod_headers.c>
  Header unset ETag
</IfModule>

# Since we're sending far-future expires, we don't need ETags for
# static content.
#   developer.yahoo.com/performance/rules.html#etags
FileETag None


# ----------------------------------------------------------------------
# Stop screen flicker in IE on CSS rollovers
# ----------------------------------------------------------------------

# The following directives stop screen flicker in IE on CSS rollovers - in
# combination with the "ExpiresByType" rules for images (see above).

# BrowserMatch "MSIE" brokenvary=1
# BrowserMatch "Mozilla/4.[0-9]{2}" brokenvary=1
# BrowserMatch "Opera" !brokenvary
# SetEnvIf brokenvary 1 force-no-vary


# ----------------------------------------------------------------------
# Set Keep-Alive Header
# ----------------------------------------------------------------------

# Keep-Alive allows the server to send multiple requests through one
# TCP-connection. Be aware of possible disadvantages of this setting. Turn on
# if you serve a lot of static content.

# <IfModule mod_headers.c>
#   Header set Connection Keep-Alive
# </IfModule>


# ----------------------------------------------------------------------
# Cookie setting from iframes
# ----------------------------------------------------------------------

# Allow cookies to be set from iframes (for IE only)
# If needed, specify a path or regex in the Location directive.

# <IfModule mod_headers.c>
#   Header set P3P "policyref=\"/w3c/p3p.xml\", CP=\"IDC DSP COR ADM DEVi TAIi PSA PSD IVAi IVDi CONi HIS OUR IND CNT\""
# </IfModule>


# ----------------------------------------------------------------------
# Start rewrite engine
# ----------------------------------------------------------------------

# Turning on the rewrite engine is necessary for the following rules and
# features. FollowSymLinks must be enabled for this to work.

# Some cloud hosting services require RewriteBase to be set: goo.gl/HOcPN
# If using the h5bp in a subdirectory, use `RewriteBase /foo` instead where
# 'foo' is your directory.

# If your web host doesn't allow the FollowSymlinks option, you may need to
# comment it out and use `Options +SymLinksOfOwnerMatch`, but be aware of the
# performance impact: http://goo.gl/Mluzd

<IfModule mod_rewrite.c>
  Options +FollowSymlinks
# Options +SymLinksIfOwnerMatch
  RewriteEngine On
# RewriteBase /
</IfModule>


# ----------------------------------------------------------------------
# Suppress or force the "www." at the beginning of URLs
# ----------------------------------------------------------------------

# The same content should never be available under two different URLs -
# especially not with and without "www." at the beginning, since this can cause
# SEO problems (duplicate content). That's why you should choose one of the
# alternatives and redirect the other one.

# By default option 1 (no "www.") is activated.
# no-www.org/faq.php?q=class_b

# If you'd prefer to use option 2, just comment out all option 1 lines
# and uncomment option 2.

# IMPORTANT: NEVER USE BOTH RULES AT THE SAME TIME!

# ----------------------------------------------------------------------

# Option 1:
# Rewrite "www.example.com -> example.com".

<IfModule mod_rewrite.c>
  RewriteCond %{HTTPS} !=on
  RewriteCond %{HTTP_HOST} ^www\.(.+)$ [NC]
  RewriteRule ^ http://%1%{REQUEST_URI} [R=301,L]
</IfModule>

# ----------------------------------------------------------------------

# Option 2:
# Rewrite "example.com -> www.example.com".
# Be aware that the following rule might not be a good idea if you use "real"
# subdomains for certain parts of your website.

# <IfModule mod_rewrite.c>
#   RewriteCond %{HTTPS} !=on
#   RewriteCond %{HTTP_HOST} !^www\..+$ [NC]
#   RewriteRule ^ http://www.%{HTTP_HOST}%{REQUEST_URI} [R=301,L]
# </IfModule>


# ----------------------------------------------------------------------
# Built-in filename-based cache busting
# ----------------------------------------------------------------------

# If you're not using the build script to manage your filename version revving,
# you might want to consider enabling this, which will route requests for
# /css/style.20110203.css to /css/style.css

# To understand why this is important and a better idea than all.css?v1231,
# read: github.com/h5bp/html5-boilerplate/wiki/cachebusting

# <IfModule mod_rewrite.c>
#   RewriteCond %{REQUEST_FILENAME} !-f
#   RewriteCond %{REQUEST_FILENAME} !-d
#   RewriteRule ^(.+)\.(\d+)\.(js|css|png|jpg|gif)$ $1.$3 [L]
# </IfModule>


# ----------------------------------------------------------------------
# Prevent SSL cert warnings
# ----------------------------------------------------------------------

# Rewrite secure requests properly to prevent SSL cert warnings, e.g. prevent
# https://www.example.com when your cert only allows https://secure.example.com

# <IfModule mod_rewrite.c>
#   RewriteCond %{SERVER_PORT} !^443
#   RewriteRule ^ https://example-domain-please-change-me.com%{REQUEST_URI} [R=301,L]
# </IfModule>


# ----------------------------------------------------------------------
# Prevent 404 errors for non-existing redirected folders
# ----------------------------------------------------------------------

# without -MultiViews, Apache will give a 404 for a rewrite if a folder of the
# same name does not exist.
# webmasterworld.com/apache/3808792.htm

Options -MultiViews


# ----------------------------------------------------------------------
# Custom 404 page
# ----------------------------------------------------------------------

# You can add custom pages to handle 500 or 403 pretty easily, if you like.
# If you are hosting your site in subdirectory, adjust this accordingly
#    e.g. ErrorDocument 404 /subdir/404.html
ErrorDocument 404 /404


# ----------------------------------------------------------------------
# UTF-8 encoding
# ----------------------------------------------------------------------

# Use UTF-8 encoding for anything served text/plain or text/html
AddDefaultCharset utf-8

# Force UTF-8 for a number of file formats
AddCharset utf-8 .atom .css .js .json .rss .vtt .xml


# ----------------------------------------------------------------------
# A little more security
# ----------------------------------------------------------------------

# To avoid displaying the exact version number of Apache being used, add the
# following to httpd.conf (it will not work in .htaccess):
# ServerTokens Prod

# "-Indexes" will have Apache block users from browsing folders without a
# default document Usually you should leave this activated, because you
# shouldn't allow everybody to surf through every folder on your server (which
# includes rather private places like CMS system folders).
<IfModule mod_autoindex.c>
  Options -Indexes
</IfModule>

# Block access to "hidden" directories or files whose names begin with a
# period. This includes directories used by version control systems such as
# Subversion or Git.
<IfModule mod_rewrite.c>
  RewriteCond %{SCRIPT_FILENAME} -d [OR]
  RewriteCond %{SCRIPT_FILENAME} -f
  RewriteRule "(^|/)\." - [F]
</IfModule>

# Block access to backup and source files. These files may be left by some
# text/html editors and pose a great security danger, when anyone can access
# them.
<FilesMatch "(\.(bak|config|sql|fla|psd|ini|log|sh|inc|swp|dist)|~)$">
  Order allow,deny
  Deny from all
  Satisfy All
</FilesMatch>

# If your server is not already configured as such, the following directive
# should be uncommented in order to set PHP's register_globals option to OFF.
# This closes a major security hole that is abused by most XSS (cross-site
# scripting) attacks. For more information: http://php.net/register_globals
#
# IF REGISTER_GLOBALS DIRECTIVE CAUSES 500 INTERNAL SERVER ERRORS:
#
# Your server does not allow PHP directives to be set via .htaccess. In that
# case you must make this change in your php.ini file instead. If you are
# using a commercial web host, contact the administrators for assistance in
# doing this. Not all servers allow local php.ini files, and they should
# include all PHP configurations (not just this one), or you will effectively
# reset everything to PHP defaults. Consult www.php.net for more detailed
# information about setting PHP directives.

# php_flag register_globals Off

# Rename session cookie to something else, than PHPSESSID
# php_value session.name sid

# Disable magic quotes (This feature has been DEPRECATED as of PHP 5.3.0 and REMOVED as of PHP 5.4.0.)
# php_flag magic_quotes_gpc Off

# Do not show you are using PHP
# Note: Move this line to php.ini since it won't work in .htaccess
# php_flag expose_php Off

# Level of log detail - log all errors
# php_value error_reporting -1

# Write errors to log file
# php_flag log_errors On

# Do not display errors in browser (production - Off, development - On)
# php_flag display_errors Off

# Do not display startup errors (production - Off, development - On)
# php_flag display_startup_errors Off

# Format errors in plain text
# Note: Leave this setting 'On' for xdebug's var_dump() output
# php_flag html_errors Off

# Show multiple occurrence of error
# php_flag ignore_repeated_errors Off

# Show same errors from different sources
# php_flag ignore_repeated_source Off

# Size limit for error messages
# php_value log_errors_max_len 1024

# Don't precede error with string (doesn't accept empty string, use whitespace if you need)
# php_value error_prepend_string " "

# Don't prepend to error (doesn't accept empty string, use whitespace if you need)
# php_value error_append_string " "

# Increase cookie security
<IfModule php5_module>
  php_value session.cookie_httponly true
</IfModule>

# ExpressionEngine Rewrite

<IfModule mod_rewrite.c>
  RewriteCond %{REQUEST_FILENAME} !-f
  RewriteCond %{REQUEST_FILENAME} !-d
  RewriteCond $1 !.(\.css|\.js|\.png|\.jpe?g|\.gif|\.ico)$ [NC]
  RewriteRule ^(.+)$ index.php/$1 [L]
</IfModule>

Answer 2

The problem I was experiencing turned out not be related to ExpressionEngine. The host I was using had an incorrectly configured mod_security Apache extension which was - for reasons unknown to me - sending a 404 whenever ExpressionEngine came to submitting the post.

Since I was using shared hosting I was not allowed to configure it myself, but my understanding was the server misconfiguration was to blame for the issue. Since requesting mod_security to be toned down for my EE site, the post functionality worked perfectly fine.