May 13 2019 08:18 PM
May 13 2019 08:18 PM
I have a Teams channel setup to accept emails from anyone (as in, there are no sending domain filters set).
If I email this channel directly from my Office 365 or GMail accounts, the messages are displayed. However when I route the email from a smart-host (it's a custom setup, not an off the shelf package) then the message doesn't get through.
I can setup the smart host to send to my Office 365 mailbox address and the Teams address at the same time - I get the message but Teams does not.
Does anyone know if Teams is checking DKIM signing on the message, or if there's a SPAM filter of some kind? My smart host does not (yet) apply DKIM signing to the messages it routes, so I'm wondering if that's the issue.
The SPF records are set properly but the message content I've been using has been "test" this and "sample" that, which can end up in Junk sometimes.
May 13 2019 10:14 PM - edited May 13 2019 11:42 PM
May 16 2019 02:00 PM
May 17 2019 03:47 AM
Thanks @Christopher Hoard - that's not quite what I meant.
Firstly, the "smarthost" is of my own making and isn't greylisting anything. It's a mail router that you can send email to and will forward that email on to another mailbox for you. I have setup a rule that the target for the router is a Teams email address (and an Outlook mailbox - I can have more than one target). The Outlook mailbox receives the message, so the router is obviously working, but the Teams channel never does. This means the Teams mail feature must be rejecting the message.
I noticed that the router does not strip out the original DKIM headers when the mail comes in. This means the message would definitely fail DKIM validation. That's enough to send the message to the Outlook spam folder... I wonder if it's enough to also prevent the message from getting through to Teams.
I have a new build of the router that I'm testing that resets the DKIM headers properly - we'll see if this solves it!
May 17 2019 03:50 AM
Jun 24 2019 10:20 PM
@Chris Webb So we updated the message router so it now properly signs messages with DKIM; I also have the system emailing me copies of any messages that come through. So I **know** the messages are being sent on to the Teams channel, but they never appear in the list.
Is there any way to debug this? Messages sent to Teams are not ever getting into the channel which is a serious problem for us right now.
Jun 25 2019 04:15 AM
Jun 25 2019 08:20 AM
Jun 25 2019 09:02 AM
Jun 25 2019 09:06 AM
Jun 25 2019 09:11 AM
Jun 25 2019 09:13 AM
Nov 07 2019 11:35 AM
Mar 29 2020 05:35 PM
I found that emails with key words such as "Voicemail" or other kind of emails were filtered out. I traced email through Exchange and it was successfully delivered but once it goes to teams it is a "BLACK HOLE"... clearly there is spam filtering going on which we have NO control on or ability to whitelist etc.
Aug 14 2020 07:17 AM
Sep 17 2020 04:34 PM
Also throwing in my experience here - Teams channel emails seem to be blocking an entire domain of mine with no way to really tell what's going on. I can't send anything from that domain to a teams channel email in an organization that I own nor to ones that I don't own. In the org that I do own, I've added the domain as an approved one, I've tried allowing from all domains, but nothing.
Opened a ticket with Microsoft but the support agent that I've been talking to just isn't understanding my problem. It feels like there is in fact some kind of spam filtering going on and it's really frustrating to me that even manually approving the domain seems to do nothing.
Aug 19 2021 01:08 AM
I found the issue my side , if you are using a smart host , bypass is
Sep 21 2021 07:29 AM
Sadly, I can mirror your experiences. I've had multiple tickets with Microsoft about their routing of e-mail from Exchange Online into Teams and it seems like nobody has a handle on diagnosing the routing within Teams. I can't find any diagnostics beyond seeing e-mail heading to the Teams address and then vanishing with no rhyme or reason. @mikewoodld