I don't know as I can't see your attached file (yet). Non-Compliant usually means it doesn't meet the submissions requirements or it's not allowed to be used commercially as desribed in the Stock Contributor User Guide.
Remove that signature & date from your submitted photos. Stock is not an art gallery. Stock images are used for commercial purposes: products, merchandise, marketing, videos, TV ads, etc...
Also don't crop images too tightly. You clipped the bird's tail which makes this image less desirable for purchase.
Including your watermark makes it non-compliant; however even if you remove that I think it will be rejected on the basis of technical issues - primarily focus because the head and beak are not in sharp focus.