The submission process doesn't work in a personal developer instance (PDI: an instance where the URL starts is something like dev12345.service-now.com). Because the process involves moving an app between instances it's not enabled for PDIs.

In a real-world scenario you would be moving the app between dev, test, and production instances and that pipeline would need to be setup. If you're in a company's development environment, then you would either need to talk to an admin or set up the development pipeline.

Are you using a PDI?