At the start of a multiplayer server with the mod on, I chose Phantom. Unfortunately, each time I die my game glitches. Once I respawn I lose the phantom ability (I can't toggle phantom mode and I see myself solid instead of transparent, although I still have the correct amount of hearts, and the other players can't see me. I tried leaving and rejoining the server but it left me on "Connecting to server..." for a few minutes before disconnecting me. It helped to restart the server and then join again but now it won't work anymore.
We use Aternos as our server supplier, and I am the only one in the group who has the bought version of the game if it matters. We are not using any major mod that could conflict with this mod.

I also tried to change my origin with the command to human and back to phantom but it still wont work

Can you send your client output log (usually located in the .minecraft/logs directory) and the server's output log (usually located in the logs directory in the server's directory)?