[Решено] Website Issue

Background of the issue:
I am trying to navigate my site, but it keeps breaking down and gets errors like this regularly. Link to a page where the issue can be seen: скрытая ссылка

Symptoms:
Internal Server Error. The server encountered an internal error or misconfiguration and was unable to complete your request. Additionally, a 500 Internal Server Error error was encountered while trying to use an ErrorDocument to handle the request.

Questions:
Why does my site keep breaking down and showing an Internal Server Error?
Can you please check and let me know what is causing this issue?