OK Start with that: I wanted to play gtm, because i liked it from one youtuber. When i copied the server IP and I launched it in Minecraft There was wroten somethingh like this:Failed to login: Acces token cannot be null or empty. sorry if i wrote somethigh wrong because I am from Poland.
To fix this just simply reboot your Minecraft again and it'll be fixed. P.S, I always run into this problem when I leave my Minecraft afk in the Menu