Can you open any other applications on those ports? I would check that out because it may be a permission issue, I had a similar problem on linux before. Take a look at the Configuration - Streamlit Docs and then on your permissions. I hope this helps.
I’m facing the same issue, @cualr to check the permission issue, I initially run it on port 8501 then on 8502. streamlit app ran successfully on both the ports, just I need run the app one at a time. When I try to run two apps simultanously, I can’t.