The gamertag was changed and the permitions on Microsoft account. Minecraft did not changed to the new gamertag with the correct permitions.

Log out and log back into your xbox live account

Cleaning up old tickets: This ticket had been set to 'Awaiting Response', but has not received a response from the reporter (~3 months+) so is being closed as Incomplete. If you feel this is still a valid issue then please comment, or create a new ticket following the Issue Guidelines which includes steps to reproduce the problem.

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