I created a new GAE app, but the Cloud Integration section on the Settings page tells me that "An error occurred when creating the project. Please retry."
I have pressed the Retry button multiple times over a period of many hours, but it's just not working. I found this thread, which repeatedly says that the issue is solved, but it's not resolved for me.
Is anyone from Google monitoring this forum? Can you help?
The only solution seems to be to create a new app, and hope for the best (it worked for me). Sadly, if you delete the problem app, the app-id is lost forever.
This is a bit late, but in case someone else stumbles on this question.
In the google cloud console, activate billing from the Storage>Cloud Storage > Browser tab, then activate / retry under Cloud Integration from appengine.google.com.
I didn't need to create a new app id, when I went that route.