Voicemails marked as EXTERNAL MESSAGES - Prevent Phishing but how?

Copper Contributor



If we our any of our customers activate Voicemail within Teams, they get the following email:


2022-04-29 10_53_59-Posteingang - k.osthoff@osthoff.net - Outlook.png


Normal not technical well trained users will not open any attachements, because outlook says, that this email came from outside the organization.


Only workaround is to use only the Teams client itself.


2022-04-29 10_52_48-.png


Okay. It seems a nice workaround, but not for any customer.


Any idea how i can disable the "outside organization"-Information ONLY for that VOICEMAIL from teams?


6 Replies



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I too am alarmed by this.


In a world where we constantly remind staff of the potential dangers of external emails, why is a valid MS Teams email notification being marked as such.


Will log with MS Support, and share any useful response.


@kai_osthoff did you ever find a fix for this? 

@Glenn Coolong 


I ended up adding a bespoke transport rule which detects messages of type voicemail and pre-fixed a message on them.


I also raised as an enhancement request through unified support. 




@Ben_pyett thanks. Is there something in that (maybe what you blocked out) that narrows down the scope so that you know it's actually from Teams and not a phisher?

Afraid not that was merely organisation specific content and URLs.


What is annoying is that MS Spoof the email as if its come from the external number rather than use an easily detectable microsoft.com email domain - this is the point I raised with their support.

Although I've yet to see a "phish" email which has successfully flagged itself as type "Voicemail"

I've obviously seen the old classic - "You have new Voicemail" phish emails, which tend to come with attachments and dubious links.

Has anyone seen this type spoofed ?