Forum Discussion
Distribution List to Teams Channels not delivering all messages
Hi all - no luck even getting a call back from Microsoft so any help would be massively appreciated
We are a Fire and Rescue Service and each of our 48 Fire Stations has a Teams account which is email enabled. The Teams sites consist of several Channels that receive email from other member of the Service.
On occasions we need to send emails to several channels simultaneously, so we have created Distribution Groups to do this.
To do this we created 20 Shared Mailboxes with the external email address of 20 different Teams Channels. (We also tried creating Contacts but have the same issue.)
We then created a Distribution Group and added the 20 Shared Mailboxes.
On sending an email from an internal email address to the distribution group only 16 out of the 20 channels in the distribution list receive the email.
Each time we test the distribution it is not always the same 16 channels that receive the email. We know each address is valid and working as we can send to each Shared Mailbox individually.
In Exchange Admin Centre we ran a Trace on one of the addresses where the message was not delivered and the initial view shows the message was delivered, however on checking the Message Events it show that it was dropped.
This is the output from the Trace
Subject: Test
Sender: ???????@southwales-fire.gov.uk
Recipient: ?????@southwales-fire.gov.uk
Received -> Processed -> Delivered
Status: The message was forwarded to the Inbox folder of the following addressRedirected to: email address removed for privacy reasons
Date (UTC+00:00) | Event | Detail |
------------------------------------
7/19/2023, 11:46 AM | Redirect | The message was directed to email address removed for privacy reasons.
7/19/2023, 11:46 AM | Drop | Reason: [{LED=250 2.1.5 RESOLVER.FWD.Forwarded; recipient forwarded};{MSG=};{FQDN=};{IP=};{LRT=}]
7/19/2023, 11:46 AM | Send external | Message sent to uk-teams-ms.mail.protection.outlook.com at 104.47.20.36 using TLS1.2 with AES256
More information
Message ID:<email address removed for privacy reasons>
Message size | From IP | To IP
22.16 KB | 159.86.187.71 | null
On Remote Domains Automatic forwarding is allowed.
Cheers
H
Hi HeatherM-SWFRS,
I will try to analyse your issue and provide some general solutions.
According to the trace data, the message titled "Test" was initially directed to the email address associated with the Teams channel. However, it was subsequently dropped with the reason code "250 2.1.5 RESOLVER.FWD.Forwarded; recipient forwarded."To be more specific, the message events in the trace indicate the following event:
Redirect: The message was initially directed to the email address associated with the Teams channel.
Drop: The message was dropped with a reason code "250 2.1.5 RESOLVER.FWD.Forwarded; recipient forwarded." This indicates that the message was forwarded to another recipient, and the original recipient (Teams channel) was considered a forwarder. As a result, the message was dropped and not delivered to the Teams channel.
Send External: The message was sent externally to the "uk-teams ms.mail.protection.outlook.com" server, which indicates it was processed by the Microsoft 365 mail protection service before being forwarded externally.
Based on this, the key issue lies in the message being treated as a forwarded message. It appears that the email sent to the Distribution Group is being forwarded to the Teams channel, and this forwarding behavior is leading to the message drop.
To try to resolve this issue you can try this:
Check for any forwarding rules or configurations set up for the Distribution Group that might be causing the message forwarding to the Teams channel.
Review the configuration of the Distribution Group and ensure that it is not set up to automatically forward messages to external addresses.
If there are any connectors or transport rules in place, review their configurations to verify that they are not causing conflicts with message delivery.
Double-check the mailbox settings of the Teams channel to ensure that it is allowed to receive external emails and is properly configured to receive messages from the Distribution Group.
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Kindest regards,
Leon Pavesic
Hi LeonPavesic
Thanks for your response - I have tried three recommended ways of creating distribution lists to send to Teams channels but get the same results with each option - out of twenty addresses only a maximum of sixteen will get delivered.
I have no rules on the Distribution list, I have a Rule that adds a disclaimer if the email address is from a company Teams address, but this stops processing other rules if the conditions are met.
Teams allows emails to be sent to channels, if I send a message to each channel individually using the entry used in the distribution list then all are delivered.
Very stumped on this as I would not consider twenty to be a number that would be caught in any spam filters - any further suggestions welcome as Microsoft support just ask for my availability - ignore it then ask for it again - beyond frustrated now.
Thanks
Heather
Personally I would use a completely different approach. The mechanism to send emails to channels isn't very easy to manage, it has it's own email filtering with a default configuration you can't configure..
My recommendation would be to use Shared Channels, so you have one overall Team and share a channel from there with each of your individual Teams. Your users will see it as a channel among their existing channels, but they all see the same content. Post your announcements in there, mention @everyone and they will all get notified. They can even react or reply to the messages for all to see.
Other than that there is an extension called Company Communicator that Microsoft provide but would need some Azure resources to deploy. It allows you to author a message and deliver it to users as a personal message to each of them.
HeatherM-SWFRS another option could be to use PowerAutomate. You could create a flow that posts a message to all the channels.
