What issued may have caused this photo to be rejected?

I would shorten the foreground and remove the distracting partial crane.

The refusal was Quality Issues? Or IP violation? You have exposure issues. I would have also croped out that "thing" left down. In addition there are artefacts with the irons. The yellow tape normally contains a logo or a company name. Sometimes it also reads danger, but companies really like to put their name there. I would delete what is written there to avoid IP issues.