Report can't be sent

I’ve created a report in Looker Studio. I can download it manually without issues but it won’t be sent by schedule, nor can it be sent now

The tiny error message below says “the report can’t be sent”

I can’t find more info about that. I reconnected my data sources (only Google Sheets in this case) and I don’t get any other error messages. Can someone help please?

Well… This report has been created directly out of Google Sheets (via Add-ons) which I haven’t done before. All my other reports I created manually from scratch, adding the data sources manually. This is the only difference to the normal working reports.

I re-created the whole report and now it works fine.

So this can be closed.