A fatal error has occurred this connection is terminated (Stoneblock)

I was playing the stoneblock modpack with my friend for two or so weeks with no issues. I opened a chance cube in the mining dimension and one of those crystals that heals the ender dragon appeared and blew up. When I hit respawn I was faced with a screen that said "A fatal error has occurred this connection is terminated". Everytime I tried to get in the server i was met with the same error. Tried many different things but im unable to get on the server using my account. I tried with a second account my friend had and logged in perfectly fine. The issue only shows up when I try to join as my accounts character. Is there any solution to this problem?

How can I do that. I was thinking about that but the only way I know how to would be downloading the world deleting the data there and reuploading it but the world is too big to upload and I have no idea how to edit a modded world with MC Edit.