Cannot clear cache without generating Error 500

[ghost_mutt]

Hi all, getting very frustrated with constant 500 errors with PS and not sure if it's a bug or an environment issue our end, although we've installed PS successfully several times before on the same server setup. Any assistance troubleshooting would be much appreciated.

Everything installs ok, but it's not possible to clear cache, change theme or save some settings in the performance screen without first getting an error 500 screen. Clicking reload clears the error and everything proceeds as normal but I cannot stop the 500 errors.

I have tried manually clearing all caches as per many threads on here and have checked file/folder permissions and file ownership too. Server settings all look healthy AFAIK and PHPPSInfo.php comes back all good also.

Getting the same problem with fresh copies of both 1.7.7.2 and 1.7.7.3.

Site is running on an NGINX/Apache VPS using Runcloud control panel.

 

In debug mode the Error translates to:

(1/1) FatalErrorException
Compile Error: ContainerUyu2frx\appDevDebugProjectContainer::load(): Failed opening required '/home/runcloud/webapps/project/var/cache/dev/ContainerUyu2frx/getPrestashop_UserProviderService.php' (include_path='/home/runcloud/webapps/project/vendor/pear/pear_exception:/home/runcloud/webapps/project/vendor/pear/console_getopt:/home/runcloud/webapps/project/vendor/pear/pear-core-minimal/src:/home/runcloud/webapps/project/vendor/pear/archive_tar:.:')

in appDevDebugProjectContainer.php line 2599

 

Please help - pulling my hair out!
TIA.