Originally Posted by lotemblizej

I had the same problem booking flights on the Austrian website recently. It said the card number or format was invalid, and I tried several times. I also have the Austrian app installed and found that when I pulled up the ticketed reservation in the app, it allowed me to add my UA MP number there. If that doesn't work, it might be possible to pull up the Austrian reservation in the Lufthansa app (all of my OS reservations show up on LH app too) and add the UA MP # there. Anyway, I found both OS and LH to be quirky at accepting UA MP # for tickets I've booked, so good luck.

And good luck with your monthly commute, if it's in C class I am incredibly envious, if in Y, then try to upgrade!