Distribution group members not receiving emails from internal users

[zimbo77]

Hi,

I have a weird issue with distribution groups. Members in the group do not receive any emails sent the group from other internal users. There are no errors on the senders or receipts side.

Emails sent to the distribution group from outside the organization work fine.

Is there something I can do to fix this?

Thanks

[#2]

Run a message trace to get an idea of what;s happening: https://docs.microsoft.com/en-us/microsoft-365/security/office-365-security/message-trace-scc

[#3]

Hi @zimbo77 

There was a similar situation too. However, the issue was because there was a transport rule set to route the emails from within the organization to a third party filtering service provider for signature and then delivered to the users mailbox. (saw this in message trace as well)

We turned off the rule, and tested and the emails were delivered successfully.

Let me know if this helps.