all my edit button cannot work and got "Invalid form POST data" AJAX error I don't know why all my edit button doesn't work since yesterday. In the log report, I got an AJAX HTTP error with 200 HTTP Code and "Invalid form POST data." message. And when I clicked any "edit" button, I received an Ajax error without any response Text:


Here are some buttons I found which don't work any more:


From Feed Import Setting (edit button doesn't work):

From Content type Adding (add existing product button doesn't work):



Does anyone have any idea why I got this???
An AJAX HTTP error occurred is very general error and it can be related to many things.

Based on your provided information we can say it's a core callback (/system/ajax) and the callback exists (Result code: 200).

The main problem is that it returns the empty response. This is most likely caused by WSOD (white screen of death) which can be related to:


out of memory issue (increase memory_limit in your php.ini),
timeout issue (increase max_execution_time in your php.ini),
code issue (make sure you don't have any exit() or die() which terminates your code),
cache issue (so please clear your cache, including memcached/redit if you're using it).


To debug this, you should:


Check your watchdog table for any errors (e.g. drush ws --tail --full).
Check your PHP error log for any PHP errors.
Use XDebug PHP extension, after configuring it enable xdebug.auto_trace parameter (only temporary), then reproduce the problem and check the trace file for more details.