We have exactly the same issue with the MSC Cruises website and despite reporting it to them, there appears to be little to no interest to fix it, as they have deliberately applied this website barrier for users.
Therefore, as in our case if you have purchased your trip from a different country than you live in, which is the case for us, then the bug will kick in and make it impossible for you to use the customer platform for e-ticket processing, tour bookings, etc.
If the airlines applied the same logic to their customer websites, it would for sure not go well with the customer base and it would be fixed in less than 24 hours..........fail to understand the logic by MSC Cruises, creating a bad start and experience for your next cruise trip!
