Google App Engine : this application does not exist

You have to make sure that application name in your GAE local client matches the one in your Google account. Check the app.yaml file to make sure that the name of application matches there as well.

That happened to me as well when I provided a username that wasn't an owner/developer, and even specifying a different account with -e or --email didn't work. What fixed was this:

appcfg.py update . --no_cookies

(same as: https://stackoverflow.com/a/10004722)

That also happend to me when I change the email to create new appid for goagent.

My solution is delete cookie file in the server directory:

rm server/.appcfg_cookies

then, everything is ok!

You have to login under developer or owner to deploy application. This is bottom left icon in eclipse.

Also check your application name. If id of application correct and user you login has role owner/developer for this application - you will deploy.