Hello Alexander McDonald,
Welcome to Microsoft Q&A forum.
I see that you are having issue with the signing in to the Minecraft Launcher. Before we proceed, may I know if you are having issue to any other Microsoft apps and Services?
In the meantime, please try out these fixes.
- Disable IPv6
- Type "Control Panel" in the search bar and press Enter.
- Go to Network and internet > Network and Sharing Center > Select your connection > Properties.
- Uncheck "Internet Protocol Version 6/IPv6"
- Select "OK" and Apply.
- Reset the apps and try again.
- Resync the clock.
- Go to Settings > Time & language > Date & Time.
- Make sure "Set time automatically" and "Set time zone automatically" is set to enabled.
- Click "Sync now" to resync the clock.
Additionally, you can create another user profile and see if the issue persists in that profile.
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