'An unknown error has occurred.' when updating a facebook group's cover_url

Question

How do I successfully update a facebook group's cover_url through the graph api? No matter what I try, I get an error on the 3rd step from below:

1. Create a group by POST /APP-ID/groups DOCUMENTATION: https://developers.facebook.com/docs/graph-api/reference/v2.5/app/groups#publish
2. Get the returned GROUP-ID
3. Using the same access_token, POST /GROUP-ID with cover_url param DOCUMENTATION: https://developers.facebook.com/docs/graph-api/reference/v2.5/group/#update

The error I'm receiving is in the form:

{
   message: 'An unknown error has occurred.',
   type: 'OAuthException',
   code: 1,
   fbtrace_id: <SOME-ID>
}

I'm imagining there's some restriction on valid cover photos, but neither the documentation or the error give me any indication as to what that is.

I submitted a bug report to facebook in the case this is legitimately a facebook bug: https://developers.facebook.com/bugs/425584494232936/

Answer 1

Turns out, this is an issue with the facebook api itself.