Thank you for helping here @Michael!
@Nick What Michael said is correct. The backup files are encrypted with the password you were using for mSecure at the time they were created. When you attempt to restore the backup, you have to enter the password you were using to open the mSecure at the time the bakcup was created.
Nick
I have just upgraded my phone from an iPhone 13pro max to the 16 pro max. mSecure did not recognise my password in the new phone so I went thru the reset knowing I had a backup from a few month back. I also upgraded my subscription from the previous free (originally paid years ago) to the pay version now. When I select the backup to restore it asks for a password. When entering my new password it fails to recognise it. Help! I am lost without this data...