Hi When i try to join a server it give me an error : You are not logged into your Minecraft account. If you are logged into your Minecraft account, try restarting your Minecraft client I tried restarting and logging off and on It only happen in some server @MojangSupport

Well you can start by using the official client instead of using a 3rd party and then bugging support when something doesn't work.

I tried with normal launcher too