Aspect ratio submission problem

I have an image I made that I want to submit, but it told me the aspect ratio needs to be 1:1 I thought it was already, but just to be sure I did a tiny little crop with a square cropping tool, still it told me it would t work because the aspect ratio needs to be 1:1. What’s going on here? Am I doing something wrong?

I would use a tool that locks the ratio at 1:1 and auto crops for you. If it isn’t exact, you typically cannot upload the image.