I'm currently playing with a few friends on a Modded Minecraft Server (Novus (Youtube Edition) in the Technic Launcher. Yesterday I went through a Portal Gun Portal and at that moment the server crashed. Now that it is online again, they can others play normally, but when I try to join the server my game crashes and the others see the message Join / leave server both at the same time
Well, you kind of walked into the Faulty Portal and are now stuck in it.
Either you fix the bug in the plugin, or you get a new Game ID, which you get when you buy the game…
What is worth more to you
What could still help is if the admin switches the server to "offline mode" and you log in with a different name and thus create a new character, then you go ingame and do not move through the portal - then the server back to "online Fashion "and you're outside…
Or you just dispose of the defective plugin / mod.