My flask web app on heroku could not go live, even though I did all that is needed, and I show on the log build successful

Question

THIS IS THE LOGS I GOT. app[web.1]: [2020-12-13 07:39:11 +0000] [4] [INFO] Shutting down: Master 2020-12-13T07:39:11.844914+00:00 app[web.1]: [2020-12-13 07:39:11 +0000] [4]