My "group send" in outlook suddenly stopped working and getting kick back,Other members OK

Copper Contributor

I set up a group for my art class. All worked fine for years. Suddenly I cannot send messages- get undelivered kick back- and do not receive any emails from the group. Everyone else in the group has no problems


Delivery has failed to these recipients or groups:

ART GROUP (email address removed for privacy reasons)
The recipient's email system isn't accepting messages now. Please try resending your message later or contact the recipient directly.

Diagnostic information for administrators:

Generating server:
Total retry attempts: 4

email address removed for privacy reasons
Remote Server returned '421 4.3.2 Service not available'

Original message headers:

4 Replies



There is a known issue with groups that Microsoft is working on. 

You can check the status here:


Title: Users may be unable to send email to groups

User Impact: Users may be unable to send email to groups.

More info: Users that encounter this problem receive an error stating there was a delivery failure to the recipient.

Current status: Due to the complexity of the issue, the fix to revert the offending change is taking longer than expected. We're conducting additional validations on the fix before enabling it in the affected service environments to ensure it completely remediates impact, and we'll provide a timeline for remediation as it becomes available. 

Thanks Diane! Glad to see there is a recognised problem! Tried lots of work arounds today. Even got my wife to set up a new group including me, but I was still not able to send an email to this group nor able to see an email my wife contributed to the group! I can do normal direct emails without issues!


I know that you have been aware of this issue since Apr 2022, how close are you to resolving it and will a notice be sent out when it has been resolved.


Thank you

At this time, no one knows how long it will take. They don't usually send out notifications - yiou just notice its working one day.