can't join servers sometimes

Randomly minecraft won't let me join servers saying Failed to join server: Invalid Session (try restarting your game)

After restarting game
Failed to join server: Invalid Session (try restarting your game)\

Checked help.mojang.com:
sessions was "fine"
evidently it wasn't because

Failed to join server: Invalid Session (try restarting your game)

After restarting game
Failed to join server: Invalid Session (try restarting your game)

This also affects snapshots