The images have no commercial value.
Thanks Sir Ralph
Here is Adobe's definition of Non Compliant
Files may be considered noncompliant due to watermarks, inappropriate or irrelevant keywords or titles, or questionable or defamatory content. Also, if you get a reminder to provide or resolve a problem with a release and you resubmit the file without addressing the issue, we’ll reject it as noncompliant."
There could be a problem with your keywords or title, or perhaps the Moderator just clicked the wrong rejection button. I agree with Ralph that the images have no commercial appeal, because any designer can easily and quickly create this type of background without having to pay to download it from Adobe Stock.
I agree with @Ralph Lear. A blank canvas of color is nothing anybody will PAY money for.
Adobe Stock customers expect high quality professional photos of subjects they can use in commercial projects.
Better luck next time.
Thanks Medam Nancy