Don’t worry too much about rejections, sometimes they can be pretty arbitrary and some candidate types are just harder to get accepted in general for a myriad of reasons that may not be the submitter’s fault.
If you’re getting a bunch of rejections, you can try posting in the Nomination Support section of the forum to get better advice on how to improve your submissions. Forum users are infinitely better at giving useful feedback compared to the one-line generic responses in the nomination management page. At the very least, you can find out if you’re genuinely doing something wrong or if the voters/“team” are just being silly.