Maybe you problems with the name or the passcode. For example i have often Problems as my name contains a Ö which is transfered a oe but often the system make just a o instead of oe :)

You need to check the settings for the calendar in your phone and make sure that you use the gregorian calendar. 

This has been a reoccurring problem for travellers from Thailand. 

Omg thank you so much it’s work!

When you get contact with Customer Support, please let them know the solution to the problem.

You could ask them to make a note in the instructions for mobile passes that the calendar has to be set to the gregorian calendar.

IMO the app should display a warning if the calendar is not set to Gregorian.