Her clothes and sunset in the background contain too many indistinguishable colors, which my be a reason for entry denial. Try to avoid gradients and stick with smaller color palettes. If you want to create a nice transition between colors, you should try dithering, but don't overdo it. Lighting animation is pretty decent btw.
4 . Pieces must exhibit proper color palette control. Having too many similar / indistinguishable colors that serve no specific purpose may have a piece denied entry to the gallery. Use PJ Image Specs to analyze your piece for such issues.
And it seems that this gif was scaled. You should upload pieces of their original size.
Submitted pieces must not be prescaled (e.g. 2x zoom). Small files are exempt from this restriction when they serve as a preview to detail files.