Hello, I have a problem on the page with error 500 every time I install an app / plugin. Usually, I have to refresh the page twice for the forum to come up and the error to disappear. Is anyone able to help me with this? My website is m4a1.pl.

Alternatively, if there is a Pole here, I will be happy to cooperate with technical assistance.

You would need to contact the author of that application/plugin for assistance. We would not assist with 3rd party applications. Taking a look at what is showing in your server error log would be the first place to look though, if you are getting internal server errors