We are sailing in August. Don't know if you have tried since this post, but if you are arriving a day or two (in our case 3) ahead of the cruise, obviously you can't reserve shipboard dining on those days. The confusing thing is on the app your days prior to boarding the ship are listed as 'day 1, day 2, etc'. It took my s-i-l and I 20 minutes to figure out what we were doing wrong. 🙃