Cartthrob ct_pay_by_check causes 502 Bad Gateway | nginx

Question

Specs: EE 2.8.1 | CT 2.5 | PHP 5.3.5

I'm running into an issue where using the ct_pay_by_check gateway during checkout is giving me a "502 Bad Gateway | nginx" error on returning to the confirmation page, in which the order entry is set as status 'Offsite Processing'. The order is processed correctly in the backend, but does not return the confirmation page to the frontend user. I am also using PayPal Express & PayPal Pro gateways without issue on the same site, although those have only been tested on successful authorization.

I have tested this issue in both Chrome and Firefox and both give the same result. Additionally, I tested checkouts by both regular logged-in members and as superadmin both return "502 Bad Gateway | nginx".

Testing on my local system running WAMP had no issues, so I'm assuming there is something about the live server configuration that might be causing this. However, I'm at a bit of a loss as to what might need tweaking.

Answer 1

I did a search for '502 bad gateway nginx' and it is a fairly common issue, and seems to be more server configuration related than it is a software issue. I was able to resolve my instance of the error by inserting the following values within the http {} tags in the nginx configuration file located on my server at /etc/nginx/nginx.conf :

proxy_buffer_size 128k;
proxy_buffers 4 256k;
proxy_busy_buffers_size 256k;

Then restart the nginx service via SSH with the command 'service nginx restart'

This information is referenced from the following sources:
Source 1
Source 2