Suggestions on why rejected?

A shutter speed of  1/2500 sec is way too high for a 18-35mm lens. Cut back to under 1/200 sec to reduce the ISO, which should be set to "Auto". Carefull where you make your light metering. Correct exposure issues in post processing.

Hello,

The shutter speed isn't the problem with the focus. You already have a high shutter speed 1/2500. The ISO is also high - 3200.

I think the problem is because of the lens. Did you use a kit lens with your camera? The kit lens that comes with the 'cheaper' (even though they are not so cheap) DSLRs isn't very good, (they are made cheaply so as not to introduce more cost to the camera), the result is even though you focused well, the focus still looks bad. 😞 Like in your examples. I'm afraid to say that by using this lens, the quality won't be so good.

Using a tripod can help in low light conditions, like in the forest because you can use a lower shutter speed and lower ISO. Having a high ISO introduces noise.

You were advised by the Moderator of the rejection reason, which appears to be "Technical Issues". The first image is quite underexposed, not in focus and has chromatic aberration and leaning verticals. I'm not certain because it's so dark, but you might have also some IP violations if there are signs or logos that identify specific properties. The second image is also underexposed, lacks sharp focus, and exhibits chromatic aberration.