The following article is meant only for customers with a standalone installation of Post Affiliate Pro (installation on their own server).
If you run into troubles with infinite loading of your merchant and affiliate panels or login forms, most probably it is caused by Pagespeed module for Apache server.
How to find out if mod_pagespeed is the cause of loading issues
If you enable a debugger in the browser, under the 'network' section, you should see a 404 error on a request to a file like this: https://URL-OF-PAP/affiliate-login-1.cache.php?ver=188.8.131.52&l=en-US.1585699844
and you can also search for the occurrence of a 'pagespeed' in the network console.
You can also check the source code and check if the pagespeed is added in the header.
How to fix it
You have two options to fix this issue.
You need to disable mod_pagespeed for Post Affiliate Pro directory on your server.
You can do it directly in the apache configuration.
Or you can disable it by adding this row into the .htaccess file of your Post Affiliate Pro: