Thank you@wouterj.

I was too fast to try the patch. I thought it fixed the issue, but I messed up with Git. Unfortunately, it does not fix the issue for me.

Hmm, I don't have time to test this locally myself today.

Thinking about it, I think there might be an issue when no enabled authenticator factory implementsEntryPointFactoryInterface. In that case,$entryPoints is still empty and simply ignored (no error). Can you maybe try (line 560):

-        if ($entryPoints) {+        if ($this->authenticatorManagerEnabled) {