Hi, @Harold-debug. You are starting a gunicorn server in the build system. The build system is intended to build your site and not to run a server.
In other words, the type of site you are trying to deploy is not able to be hosted on Netlify. You will need to find another hosting service for this site as you cannot host this type of site at Netlify.
There is more information in a another thread opened about this here: