For some reason, this only happens to me on prison, but when I relog it doesn't fix either... That would be y I quit prison, I can't even use /rankup
I am guessing you have 2 ranks, usually relogging works, if it doesn't, then you may have to ask a moderator.
relogging usually helps with rank issues on op prison. I will archive this now as this thread has been inactive a while, but feel free to create a new thread if you experience any more issues.