I go downtown in Naples Fl. and shoot buildings, street scenes, shops, but even when the shops or buildings have no identifying signs or logos they are still turned down for intellectual or property rights. It seems that everything in a downtown area is verboten. If that doesn't work there is always the fallback position of sharpness, noise or excessive post possessing or no aesthetic appeal. I have been shooting for 60 years, do my own printing and while I have had 18 photos accepted, I'm discouraged. And of course people are also verboten. I don't know what to shoot: no people and no buildings.
I appreciate the feedback. Rejections are a part of the learning process. Selling stock for commercial use has a lot of rules you need to learn and comply with. I recommend you take some time to read through the legal guidelines as this will help steer you away from potential conflicts: Stock Contributor Help
You most definitely can shoot buildings and people for stock. The catch is that you need to get the permission from the people or the owners of the building in writing as this is the requirement when you are going to use their likeness for commercial license purposes.
I do recognize how discouraging it can be to have your images rejected. As you continue to shoot and submit you will likely recognize what will succeed and won't which will start to minimize the decline messages.
I wish you the best of luck!