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Errors "Failed to login - null" or "Failed to login - invalid session" when joining a server

Issue Description

These errors mostly happen when there is a Microsoft account authentication issue on your launcher, whether it is Technic or CurseForge.

 

Authentication error example 1 Authentication error example 2

 

Solution(s)

1. Closing the game and launcher completely, logging out from the launcher, and relogging back in are the most common fixes.

2. If that still doesn't work, you can navigate to %appdata%/roaming/.technic and delete the oauth folder.

If this still doesn't resolve the issue, you can open a support ticket on our Discord server.

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