The entry I'm having problems has a Matrix field with over 100 rows, on 8 columns of data (7 simple text fields, 1 dropdown with 2 options). When attempting to add just one more row and hitting the submit button, the server seems to be choking and coming up with a the default 404 page set for the website...no error messages or anything to tell what's actually going on. Checking the PHP error logs also shows nothing up.
I've attempted to up the 'memory_limit' to 2048M and the 'max_execution_time' to 300, but neither of these makes any difference.
Running EE v2.5.5 and Matrix v2.5.10, there's are also another Matrix field, and Assets field and a WYGWAM field on this entry.
A strange thing is that I can update this entry on my local MAMP setup, but not the Production server.