Recently I got many error 500 und different sites when updating extensions in the joomla extension updater. when I refresh the error is gone. but I thought I am going to reinstall the extensions in case something is missing, went to the extension manager and reinstalled one after another. and now I get an error when I want to access the extension manager that says:
Something went wrong.

Try refreshing the page.

When I want to delete the cache, it says "Cache could not be deleted"

What is wrong?

Now, some time later, I can refresh the page and the extension manager is working again...