500 error returned on search -- seems IP dependent

Re-posting a question from the soon-to-be-sunset Facebook developers forum.

An earlier poster and I are receiving consistent 500 errors returned on fetching a URL such as:

https://graph.facebook.com/search?q=term&type=page

https://graph.facebook.com/search?q=term&type开发者_C百科=event

Receiving the 500 error seems to depend on IP address. In my case I'm making repeated searches from a Google App Engine backend; the original poster also mentioned repeated searches but didn't mention if it was GAE. In each of our cases, we get successful responses from our browser or running the same code from a different IP address.

Questions:

• Is this a standard response if an IP is blacklisted, which I suppose could happen when lots of apps share an IP range?

• Is there a suggested way to "play nicer" to avoid these errors, albeit again if we're sharing an IP range with lots of other developers, this might be out of our control?

• If it's not a blacklist issue, what could it be?