Mama2Tay

We are sailing in March and I can see all three of our cabins in my app. I did the check-in for all three, just chose the boarding time and left the rest to finish later. The problem is that my son and his girlfriend who are in one of the cabins cannot see the check-in on their app. When they go to the check-in section they get a message that check-in is not available or something similar. My daughter and her boyfriend in another cabin can see theirs just fine and so can my husband. Anyone have any idea why this is?