This post highlights notifications for likely spam calls in Microsoft Teams. The upcoming feature adds a text in the box for your incoming calls where you can answer or decline the incoming call. Microsoft detects or assumes that the caller’s number is used for spam and therefore is displaying a yellow sign with an exclamation mark plus a text label saying “SPAM LIKELY”. In the recent roadmap (August 15, 2021) feature ID 85386 and MC277640 it is said that the feature’s rollout should start in late August 2021.

Based on what indication is the call marked as “spam likely”?

As of now there is no documentation available explaining it or I did not find it.

That’s why I’d guess the following:

• Microsoft might check and analyze on how often a number is calling and/or if there is any “spam likely”-pattern detected, e.g. the number who calls is anonymous or tried to call all numbers from -0 to …
• Microsoft might use a third-party database for phone numbers which were reported as “spam likely”
• Or Microsoft uses a combination of both.
• Or any other approach which I did not came into my mind right now.

Please note, that I might update this section as soon as I notice that further documentation and an official explanation is available in the future.

How to enable or disable Microsoft Teams Spam Call Notifications?

By default Spam Call Notifications are enabled. If you want to disable it you can do this by using the Teams Shell and disable it on the respective calling policy. There are three options, not only Enabled and Disabled but also EnabledWithoutIVR.

#Disable Microsoft Teams Spam Call Notifications
#Example
#Connect
Connect-MicrosoftTeams

#Disable Spam Call Notification (per policy)
#Examaple disable it globally in your tenant using the -SpamFilteringEnabledType parameter to disable or enable it
Set-CsTeamsCallingPolicy -Identity Global -SpamFilteringEnabledType "Disabled"

#Disconnect
Disconnect-MicrosoftTeams

Conclusion, opinion and summary

In general the feature might be helpful but the technical documentation is missing at the moment. I’m not yet sure based on which approach (database?) an incoming call is marked as “SPAM LIKELY” and what the “EnabledWithoutIVR” parameter might do. I can only guess at the moment and wait until it is available and can be tested. I hope that no admin has to define his own tenant’s spam database for calls, extending it would be ok but not setting one up from scratch. Although you might could use APIs and scripting to get the data in the database but why reinventing the wheel?

In some Teams Direct Routing deployments there are also other options available using the SBC to mark or block spam calls or block it a user-level. There are some good articles out there you might want to read. Stay tuned.

Additional resources

• Microsoft 365 Roadmap feature ID 85386
• Microsoft 365 Message Center MC277640
• Microsoft Docs – Set-CsTeamsCallingPolicy
• Microsoft Docs – New-CsInboundBlockedNumberPattern
• Microsoft Docs – Get-CsInboundBlockedNumberPattern
• Microsoft Tech Community – Microsoft Teams Incoming call via Direct Route shows “Spam Likely” for 4-digit extension
• https://www.consumer.ftc.gov/articles/national-do-not-call-registry-faqs
• https://www.tellows.de/c/about-tellows-uk/tellows-api-partnership-program/
• UCIT.BLOG – Blocking Inbound Callers on an AudioCodes SBC
• UCIT.BLOG – Blocking Inbound Callers on an AnyNode SBC
• UCIT.BLOG – Blocking those Pesky Spam Callers in Microsoft Teams & Skype for Business