Failure to connect to server

Hello,
I have a sponge/pixelmon server that I run off of my pc. But for some reason I open the server, i’m not able to join, like not at all, even using Localhost doesn’t work. I tried to fix it, but everything seems to be running fine, and it’s not the ports, because I ran spigot server just to test and see if it was the ports, but that one worked, and I had a backup that used to work and it doesn’t work either, so it’s something with the files, but idk how to fix it.
Does anyone know what’s wrong?

(Going to include the mods/plugins folder in case they are part of the problem)
Please reply, i need the server up in and running in a few days

Well, if you believe it could be a mod problem, step one is to remove each mod one at a time until the problem stops. Then you know which mod it is.

Also, try using the IP address 127.0.0.1 instead of localhost.

unfortunately, that didn’t work i tried without any mods loaded and it didn’t work