I tried to check-in using the app today on a flight to US, but I was not successful.

I am traveling on ESTA and the Amadeus CI page insisted on me providing visa information, which I do not have.

I did not do the CI as I planned to drop off my bag in the evening. On the way to the airport I did get a SMS check-in message from Finnair and the BP was shown in the app.

At the check-in counter I asked if something has changed, and I was told that there has been an IT issue going on with the CI via the app to US, not allowing for CI without visa. Many passengers have then entered some ESTA related information into the Amadeus CI, but that screws up the data completely and does even CI by the agent difficult.

So, if you are asked to provide visa information and you have ESTA, just ignore the CI via the app and do the CI at the airport.