Try unmounting it, chmod the mountpoint and then make sure you have everything correctly set in fstab and remount.
Without more info than “it wont let me change” it’s impossible to know.
Edit. Is this what you are looking for? Reinstall OS where urbackup server is - #4 by rlopez
edit 2. LMAO, I just realized the answer is directed TO YOU in that post. xD