If you're having any trouble accessing the full game after migrating your account, remember to use the Microsoft login option with the account that you migrated with, and make sure to remove your old Mojang account from the launcher. See our FAQ: msft.it/6015bwSjJ. ^FF
Please complete our request form at msft.it/6018bwy8E so that one of our account specialists can look further into this issue for you. Remember to attach your Transaction ID if you have it and your account name/Gamertag. ^FF
Need a bit more information regarding the issue you're having. Can you grab me a screenshot of the error and what troubleshooting steps have you tried? ^TK
We apologize for the inconvenience, but this is currently a known issue.
The team is currently working on a fix that should fix the issue as soon as possible.
Thank you for your patience while we work on the solution! ^TK