Apr 22 2019 08:19 AM
Apr 22 2019 08:19 AM
I have an interesting problem that I've been working on for a few weeks. My organization is using Teams across the board - we're in "Teams Only" Coexistence Mode. We have a large number of teams and channels across several departments. Recently, a team was created solely for the purpose of sending e-mails to; think of it as a central point for notifications for our Marketing department.
Now, our Teams Org-wide settings dictate that users are allowed to send e-mails to a channel address. We also are set to accept channel e-mail from the domain names in our organization. Guest access is turned off, but the team in reference is internal use only.
We are a hybrid environment - users authenticate via on-prem AD, but e-mail is hosted in 365. All users have O365 Enterprise E3 licenses.
So here's where it gets weird. I can send an e-mail to the channel successfully. I'm a member of the team. I also had another user in my department send an e-mail to the channel, who was not a member of the team, and it was also successful. However, there are some users who get a NDR e-mail from 365 when they attempt to email the channel. The channel e-mail settings are set to allow e-mails sent by anyone within our domain, regardless of whether they are a member.
The team owner himself gets a bounce-back e-mail - see the attached image.
This is very confusing, seeing as our org-wide settings do not prohibit anyone from e-mailing a channel. Even more strange is the fact that some users are able to e-mail a channel, while others get a NDR.
Running a message trace on the unsuccessful attempts shows a status of "Delivered".
Any insights here?
Apr 22 2019 08:26 AM
Apr 22 2019 09:52 AM
@Chris Webb No third party tools; we have ATP enabled for safe attachments. However, there are no attachments in these e-mails. The policy is not very restrictive from what I can see. And the fact that my messages get through is very odd. All mailboxes are 365. I'm not seeing an "Allow All" option in the channel settings.
We currently have it set to allow anyone within the domain scope.
Apr 22 2019 09:55 AMSolution
Apr 25 2019 10:30 AM
@Chris Webb This solved the issue. I had to remove the entries that were in our allowed domains.
This is very strange, considering the users attempting to send these e-mails were part of the allowed domains. As soon as I removed them and set it to "Allow All" it worked.
Thanks for the suggestion! Cheers.
Apr 25 2019 10:33 AM