title: Internal Server Error when visiting the WordPress admin page
body: <p>I'm working on this site <a href="https://feinfilm.de/" rel="nofollow noreferrer">https://feinfilm.de/</a> and the front page works ok:</p>
  <p><a href="https://i.stack.imgur.com/TfGUp.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/TfGUp.jpg" alt="Front page" /></a></p>
  <p>but if I go to the admin panel <a href="https://feinfilm.de/wp-admin/" rel="nofollow noreferrer">https://feinfilm.de/wp-admin/</a>, I see this:</p>
  <p><a href="https://i.stack.imgur.com/5XKKK.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/5XKKK.jpg" alt="Internal Server Error" /></a></p>
  <p>What might be causing this issue? Thanks</p>