API returns Internal Server Error when requested by anonymous user.

I was getting this too but only when pointing urls to existing paths. For instance Drupal has an existing `/about` page and I put that path into the url, there was this error. If I made it to a non-existent path `/about-2` it works as expected.

Did you happen to resolve this?

I had to turn off rules module. Not quite sure why this resolved the issue.