i made a modded mincraft server pack for me and my friends it worked for about a week but stoped working

I tried putting in some optimization mods to make a run better than decided on deleting them due to them not helping very much and requiring too many extra downloads for the other people, but now whenever I boot it, I get this message

Starting server

Neither Forge 1.17+, NeoForge or Magma were found. Try to remove `/C:/Users/user/AppData/Local/SquidServers/world/server.jar` or reinstall the loader.

The forge file is in the server, and ive tried reloading the couple back ups i have, but nothing works