I have also had problems with OLCI recently.

I'm a U.S. citizen, Danish resident. It would not allow me to check in online because it could not find evidence that I had a valid ESTA (duh, a U.S. citizen doesn't need an ESTA).

On the return to my home in Denmark, I could not check in online because I could not give the date of when I'd be returning from abroad back to the U.S., which of course I could not do since I was returning to my home in Denmark and was completing the final leg of my round trip itinerary that started in Denmark.

Susan