Blank page on saveregisters and also when deleting a user from the admin panel

With all the plans disabled it won't let me register anymore, so I tried creating a user form the admin area in order to delete that user... I was redirected the the main admin dashboard and the user was not created. Still nothing in CBSubs' logs.
Error reporting is working though, yesterday to make sure of it I created a simple php file with just an echo statement in it and made a mistake on purpose. I got an error reported on screen. Nothing in my cPanel error logs though.

I have another website, in production, at the same host but another server... Which is running fine.
I am going to restore a backup of that problematic website on this server. I'd bet it'll work... On top of that, on this server I can choose my version of PHP. My production website is still running PHP 5.6 because I have yet to update it to the latest CBSubs, the old 4.0.1 didn't seem compatible with PHP 7. However I'd also bet that after restoring that backup which has all the latest versions, I'll be able to use either PHP 5.6 or PHP 7 with no problem... Let's see. My guess is there is something wrong with the current server. I see no other possible explanation, I've always been happy with your software I know it's top quality.

Just as I suspected... Same version of PHP (for now) and yet, after restoring a backup on that other server... I re-enabled my plans one by one... No blank page. It just works.

Signing up works flawlessly too... There's no point in trying to find where the problem is anymore. I will just have the account with the problematic website moved to the same server my other website is on.

Glad you were able to solve your issue. Not sure what server side configuration would be doing that. Blank page with no errors output or logged is often a mod_security issue.