You probably posted it in the
5th Gen Competitive Discussion section, which requires thread approval/a mod to accept it, rather than the
5th Gen RMT section which, as far as I know, doesn't require thread approval.
What you'll want to do is PM one of the Competitive Discussion mods (Ragnarok, Archangel, Gamefreak or jesusfreak94) and explain that you posted it in the wrong section, and they'll probably PM you the thread so you can repost it in the correct RMT section.
Hope this helps!