As originally reported here: https://talk.restarters.net/t/bug-report-creating-a-user-group-fails/313/5
I see this error in the logs: Address in mailbox given [[email protected];[email protected]] does not comply with RFC 2822
It looks like two email addresses have ended up combined by a ; - not sure how that happened but we’ll add something in to trap that and report to user rather than giving an exception.