Why does my character not fit the guidelines?

Your character's appearance must be somewhat natural; as a rule of thumb, we permit coat colors that occur naturally in canines. This includes colors such as black, white, gray, blue, brown, tan, and red, and markings such as socks, saddles, and patches. Spots such as those that occur in dalmatians are not permitted, but stippling of a lighter or darker shade of the base coat is. Some brindling is okay, but stripes are not. If you are unsure if something is acceptable, ask the administration.

I wasn't the one to deny you, so I can't say with 100% certainty, but it looks like that may be the culprit.