Error message "You do not have permission to modify this app" from a Google App Engine deployment

Question

I am following the instructions on http://beta.appinventor.mit.edu/learn/reference/other/tinywebdb.html , trying to create a custom TinyWebDB for a grade 10 class I teach. After creating a new Project (the instructions say create an Application, but I only see a Create a new project button), I change the project name in the local file app.yaml file, load it in, and click on Deploy. I get the following error message:

Starting update of app: npicswebdb, version: 1
01:35 PM Getting current resource limits.
2016-03-09 13:35:26,727 ERROR appcfg.py:2396 An error occurred processing file '': HTTP Error 403: Forbidden Unexpected HTTP status 403. Aborting. 
Error 403: --- begin server output ---
You do not have permission to modify this app (app_id=u's~npicswebdb').
--- end server output ---
2016-03-09 13:35:26 (Process exited with code 1)

Is there some way I need to log in to the App Engine Launcher so it connects with my App Engine in the cloud? There is nothing in the instructions about doing that, and I don't see any way to do that in the launcher.

Thanks for your help.

Answer 1

Try adding "--no_cookies":

appcfg.py -A projectname update app.yaml --no_cookies