[google-appengine] Error: Not Found The requested URL / was not found on this server.

Dear all I am trying to host a HTLML only static website on app engine...The website is www.guestworm.com and I followed this tutorial to upload and deploy my website : https://cloud.google.com/appengine/docs/standard/python/getting-started/hosting-a-static-website I get the following error

[google-appengine] Error: Not Found,The requested URL / was not found on this server.

Hello, when I want to visit my application : http://MYAPPID.appspot.com/ it says: Error: Not Found The requested URL / was not found on this server. what happened to appengine ? I cant deploy it too, when I try, it says Starting update of app: MYAPPID, version: 1 Scanning files on local disk.