failed to login invalid session (try restarting your game and the launcher)

Just restart the game, and everything should work.

I get the same issue sometimes when i keep the game opened, restarting fix everything, but i think it's still a bug and can be confirmed.

If i worked at Mojang, i would fix this by keeping track of the session validity time in the client and before it end ask to expand the session or to refresh it correctly.

Try restarting the launcher, and the game. That should fix the problem.

If that still doesn't solve your issue, please contact Community Support, linked below.

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I'm also having this issue. While restarting the game does fix this temporarily, the game session invalidates far more often than it used to. I've had to revalidate my session 3 times in one day whereas before I would only run into this issue once a month.