I've been getting this message returned in the JSON since last week when trying to get Google Classroom app usage reports via the admin api. Has anybody come across this issue before or know if it is some temporary issue with the service?
If I change the date parameters to 2020-10-12 it works and I have been able to obtain 'daily' data in this way for the last few weeks. (It seems that there is generally a delay of about 2 and half days before the reports become available for a given day, so this current delay seems to be much longer than usual).
I am using the classroom:timestamp_last_interaction parameter.
As of 2020-10-20, I can now access Classroom usage data for 2020-10-13. Maybe the lead time has increased to a week, which would be a shame, but easier to remember I suppose!
Will update if I uncover more.