What the actual hell is wrong with the Sign-Up system?

So I was creating an Alt Z8Games account today, but then I noticed that each time I insert a forum name that is not used and longer between 3-12 words... It gives me this message: "The Forum name Contains Prohibited Words" But why it always gives me that message? I mean I tried names like: GgGgGg and AAAAAA and CCCCC etc... I tried all simple names that don't mean any insult at all... So what the hell is wrong with the sign up system?!!
Edit: I just tried again now, it now gives me this message: "The forum name is already in use" each time I try a code name that no one ever used like: APDGN5464 or ASGA6G486 or 161a6763 etc... any name I use it says that it is in use, So why?!