Client stuck at encrypting, then crashes for all players connecting

This issue started when I deleted some loaded chunks in the world using an external software to load new structures with a new mod i added(amb). Since then, the server won't start up with any mods present, but without them and without this world it starts up just fine. I have tried uploading the world that was there before and it didnt do anything, i have to generate a new world for the server to work.