Anybody know somebody working on Google App Engine?

I have an app I haven't deployed for a few years. It's been chugging away providing a bit of pocket money for years. I pay google a few hundred a month in hosting.

Today I installed the gcloud tools on my new PC and attempted to deploy to my sandbox in preparation for fixing a few bugs. I've found that my Model classes now just throw "Missing or insufficient permissions" exceptions when attempting to fetch data from the data-store.

I don't really know how to go abut debugging it. I've read through the docs and as far as I can tell it should all just work.

Any suggestions?