Bytewave, his way is perfectly acceptable for the host. It's kind of a guaranteed method when done correctly.
Dallas,
HOWEVER, incorrectly modifying Gmod's file could be causing your issue. Syntax is important.
Or you're running DarkRP (with Fadmin or another conflicting admin mod), which we have 10s if not 100s of posts explaining this to others
OR you are trying to use our old "release" version of, or worse, some 3rd party release of old, ULib/ULX code (get the one from our Github site, linked from our ulyssesmod.net/downloads page) (We're trying to make a new release, we promise)
OR addons that are conflicting with group access.
OR Any combo of the above.