This is 99% most likely a problem on your side.
1) Are you running a hacked copy of Steam/HL2/Gmod? If so, this can cause all to have admin. No way to fix this (at least, no way we support)
(NOT saying you are... just a possibility)
2) Some gamemodes/addons break the admin checks of ULX/ULib. We've recently discovered problems with DarkRP.
If not the mod itself, then perhaps the way you have configured it. (even ULib itself perhaps)
2) Make sure you've followed EVERY instruction of our sticky titled "Having trouble with access?" in the Help and support forum here.
We know if you haven't, it has a lie detector test in it.
No, seriously. If you don't follow every instruction, we know.