WHMCS on Ubuntu 22.04 and Apache | Blank Page after installation

[NinerAlpha]

Hello all,

I spent 2 days trying to figure out what is wrong my my WHMCS and why every time I install it I get blank page for admin area. I did 3 fresh installs on my VPS and every time I get same results, installation runs fine and once that is done and I want to go to admin area I get blank page with: admin/login.php?redirect=%2Fadmin%2F url. If I set $display_errors = 'true' in configuration.php file I get Oops! page.

Apache2 error logs do not show anything, there are no errors listed under Oops! message and I have no idea what could cause this behavior. I opened ticket but got no useful information from support so maybe someone will have some troubleshooting tips for me. 

I am not professional apaceh2 handler so I would like to ask anyone replying to this with some advices to have understanding and explain it a bit so I could understand what is going on. 

Thanks everyone in advance.

[DemoTiger]

To get additional details, you must be logged in as an administrator in WHMCS admin.

If it does not show any additional errors, then enable display errors in the php.ini file and restart Apache.

 

Enable Apache debugging: In httpd.conf, enter the following line and restart Apache.

LogLevel alert rewrite:trace3

 

 

[SimpleSonic]

What PHP version are you using?

Have you checked that you have all the necessary system requirements for installation?: https://docs.whmcs.com/System_Requirements

Have you checked that you are using the correct folder/file permissions? (755/644 is common for most setups)

Have you tried renaming your .htaccess file to rule out any unsupported or incorrect entries?

[NinerAlpha]

My php version is set to 8.1 and all requirements are met. I switched to nginx and it works just fine with same dependenices installed, which leads me to thing I messed up something in virtualhost configuration for Apache.