com.facebook.sdk error 2 on iOS

Question

I have a Phonegap app that runs on both iOS and Android. The app has a Facebook login feature which worked until a few days ago. A few of our beta testers have reported an \

Answer 1

TRY FIRST:

Go to Settings app -> Facebook -> Your App -> Switch it off and back on again.

This worked for me, and didn't require me to actually delete the fb account and log back in as @seans23 suggests. If it hadn't worked, I would've tried that next, but this apparently did trick in resetting the state.