There are a number of reasons this type of error may be obtained. As the error message indicates, it seems there is a missing or insufficient permission and this may be due to a number of reasons. For example, on this Stackoverflow link[1], the issue was caused by missing App Engine default service account. The issue also may be caused by the App Engine service account missing the appropriate role or permission required to read and write to Datastore and Firestore databases in your Google Cloud project.
For better troubleshooting of the issue, which may involve reviewing configurations on your Project, I recommend you contact the GCP Support Engineers[2] or if you think this issue is a bug, then please open an issue using this link[3]. [1]https://stackoverflow.com/questions/59210059/datastoreexception-missing-or-insufficient-permissions-on-superseded-cloud-da#answer-59216570 [2]https://cloud.google.com/support-hub [3]https://developers.google.com/issue-tracker/#public_users -- You received this message because you are subscribed to the Google Groups "Google App Engine" group. To unsubscribe from this group and stop receiving emails from it, send an email to google-appengine+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/google-appengine/c30e2859-6268-4a35-9edf-ee2093479682%40googlegroups.com.