Open this up at 100% and look at how many parts are out of focus. It is almost as if you cut and pasted parts. Did you do post changes with filters etc.? Star looks out of focus and has a different exposure than the rest. JH
Should all parts be in focus? The depth of field is shallow, but since when is there a required standard for that? It was all one shot, and has hardly any changes, except pulling down some of the blacks and whites.
here the official explanation from Adobe's User Guide (https://helpx.adobe.com/stock/contributor/help/quality-and-technical-issues.html) about "Quality and technical issues" for a rejection:
Out of focus
Always inspect your content at 100% before submitting.
Motion blur can be used to convey speed and motion in an image or video. When you use motion blur, ensure that the main subject is sharp and in focus.
A shallow depth of field can help draw the viewer’s eye to where you want it to go. Make sure that the depth of field choice is intentional. If you shoot with a wide aperture, depth of field should enhance the photo. Make sure that shallow depth of field does not result in important elements being out of focus. If the image is in focus but lacks sharpness, ensure that any sharpening in post-production does not introduce artifacts.
I think because the main object in your picture (The Throwing Star) is not sharp enough, it was rejected. Another problem I see in the foreground, it is very noisy that may have been caused by excessive sharpening in image processing or was caused directly during shooting, depending on the range of contrast the camera can handle.
I shot it on a tripod with a timer so there is no motion blur. Also I didn't change the sharpening so it wasn't excessive. I'll try sharpening it and see if that helps it get accepted.
that you have used a tripod is no guarantee for the picture result that technical errors can not occur anyway. Some of it also depends on the camera used, the lens settings, etc.
An aperture of f3.5 generally does not offer a large depth of field range, and if you have a focal length of 30mm, which goes into the wide-angle range, you have to move so close to the object that the depth of field is reduced again. I would recommend that you inform yourself about this on the net.
You won't get the image sharper because of software-related sharpening, as the source material doesn't provide this. A blurred photo does not get sharp even in image processing. Additionally, existing image errors such as noise and artifacts are intensified.