bouncing emails in google groups

Maintaining google group by deleting bounced emails. And if needed, re-adding them. 

https://support.google.com/a/answer/7552660?hl=en

Edit: Users can reset their bounce status by going to https://groups.google.com/bounced?pli=1 or https://groups.google.com/a/example.com/groups/bounced?pli=1
next to Bounce Status, email status -> Reset bounce status. (which appears only if it is bouncing.)