We are also having the same issue with the app. When we go to order the medallions it says “unable to load”. There are six of us going and all with different phones. The problem is not our phones. When we called Princess we were told we had to use the app to order the medallions and to give it a couple of days. That was 2 weeks ago. Called again and were told exactly the same, use app and wait a few days!
We have been on the phone 4 times, 3 different people and none of us have had any success in getting dining arranged. Not inclined to book with them again.
If anyone has any suggestions please inform!