NOTE: If you have enabled a 3rd party spam filter please scroll to the bottom of this FAQ for resolving issues with the onmicrosoft.com domain email.


In some instances when creating a matter the group isn't formed properly and will bounce emails to anyone emailing/docketing calendar events to the matter. To fix this issue please find the group by searching for the matter in the 365 Admin Center and add an alias using your default domain. The group will update the email server and begin working as intended. 



Why does this happen? 


Check your default domain in the 365 Admin Center and confirm there are no issues with the domain. It will be indicated by a yellow ( ! ) warning symbol indicating that there is a configuration error. This sometimes can be due to using a third party email filter (Proofpoint, Mimecast, etc.). At this time we do not have a work around and despite the configuration being correct for the mail filtering application to work properly but Microsoft will still show an error. When this happens groups will need an alias manually assigned to begin working properly.


You can also use PowerShell to add an alias from a PowerShell session run as administrator using the command below. 


This set of commands will import and install the Exchange Online module and connect. Sign in with your tenants Global Administrator account to issue the command to add an alias.


Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope LocalMachine
Install-Module ExchangeOnlineManagement
Import-Module ExchangeOnlineManagement


Then run this command after you are connected to Exchange Online. Be sure to update the group_email@domain.onmicrosoft.com address with the specific group's email address and replace the [email protected] with the group address and update the domain. 


Set-UnifiedGroup –IdentityGroup [email protected] –EmailAddresses @{Add="[email protected]"}


For resolving groups with 3rd party email filters:


Email security filters by default only allow email from your default domain. You must follow your specific applications instructions on how to add the additional domain to allow mail to be delivered from Microsoft 365 when attempting to send mail to the defaultdomain.onmicrosoft.com email's that are generated with groups inside your tenant. Most will require updating your DNS records to prove ownership of the domain. 


We are including links to a partial list of providers, please seek support from your respective email security provider for additional guidance. 


Proofpoint - Understanding Domains


Mimecast - Email Security Cloud Gateway - Validate Microsoft 365 Tenant Domain