Have a flight to CDG tomorrow and when I tried checking in via the mobile app it gave me an error pop-up with a message about an invalid passenger id.

When I tried checking on the website I just get a "Sorry we can't check you in right now. Please speak to an agent for assistance."

Tried using browser dev tools to inspect the response object and there's an error in there that reads, "CheckinEligibility - Checkin not allowed due to Special Handling Required"

Any idea what that "Special Handling" could be? This would be my first flight with AF.

Edit:
I called AF and they weren't able to check me in from their end either.

However, it seems I ended up being able to check in from DL's website instead, even though I had booked it through AF with FB. There was even a DL PNR?

Apparently I needed to provide the date I was leaving my destination.