How to delete Mods? Can't delete them in Folder

Hey Guys,

I tried to setup a Server, after a few minutes i installed all mods i wanted and tried to start,
The Log promt with 20 Fails, I in stalled the missing mods or plugins,.
Now there are 3 mods, i can't uninstall.
I tried to remove them in the file/mods
but it doesn't work.

Thanks for every answer

Nothing happens