User registration times out/doesn't exit on live centos+nginx server I have a bit of an edge case, but it's confusing me very much. I noticed that my services user/register.json POST calls would just endlessly freeze on my production server, but not on my local, however it would actually successfully create the user. Also, it would happily exit with a services_error() callback if the user couldn't be created (existing username, for example).

On further investigation, it seems that the user registration form itself on the drupal site does the same thing. No errors come up, nothing in the logs, just an endless timeout on successful save and drupal set message errors on unsuccessful save. Even when I go into the code and insert watchdog messages, they only actually get pushed through on the next successful request. It also only seems to be registration that is affected, and creating a new user from the admin interface is completely fine.

The production server is a CentOS 7 box running nginx with php-fpm, mariadb &amp; memcached, seems to have enough memory, doesn't appear to have any weird low timeout values in the settings, etc.

Can always provide any conf files or anything if that helps, but I was wondering if anyone knew of any known issues where only user registration could be affected. Thanks in advance!
Issue was a faulty mail server. For some reason when it couldn't use mimemail properly it was choking without error, kinda annoying. Fixed by setting up a proper external mail transactor (mailjet module in my case).