Guild Name not appearing on your character?

We have a few players in the guild I help run and their experiencing "not seeing the guild name over their character's head or when they click on their own character".

Now, I'm at work and can't log into my account to verify and setting in the interface menu.

Does anyone know how to make the guild name appear?

Thanks,

Jan|||Servers are down here (maintenance), but it's in the interface menu, I think under Social.|||It's under Interface>Names.