500 internal server error when installing plugins

I am setting up a WordPress site for a client of mine. Unfortunately the client uses GoDaddy.com as a host. When trying to install new plugins, I get a ‘500 internal server’ error.

I contacted support and they couldn’t find the source of the problem on their end, they suggested it would be a compatibility issue.

Did some further digging and installed the ‘WP Maximum Execution Time Exceeded’ plugin to extend the execution time. (Note: I can’t edit the htaccess file since GoDaddy uses Plesk, which hides these files for some reason)

I needed to restore a backup I had made of my client’s previous site, and installed the UpdraftPlus plugin. The restoration process can’t complete as it also gives the ‘500 internal server’ error.

I’m at the end of my wits here, never had this problem before when setting up other sites to be honest. Any help is greatly appreciated.