Suddenly all my contacts on Teams show as "unknown contacts" and i'm also unable to continue to send teams messages

Question

Suddenly all my contacts on Teams show as "unknown contacts" and i'm also unable to continue to send teams messages

Answer 1

If your contacts in Microsoft Teams are showing as "unknown contacts" and you are unable to send messages, this could be due to several reasons:

1. Contact Offline: The contacts may be offline or have set their presence status to "Appear offline". Ensure that the contacts are signed in and available.
2. Network Issues: A network communication issue could be affecting the unified presence service (UPS). Check your network connectivity to ensure it's stable.
3. Using Skype for Business: If your contacts are using Skype for Business, this may lead to expected behavior where their presence status is not updated in Teams.
4. Teams Configuration: Verify that Teams is properly configured and running on your device. Ensure that the Teams app is installed and that you are signed in with the correct account.

If these steps do not resolve the issue, consider reaching out to your IT administrator for further assistance or check the Microsoft Community for more support.

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References:

• A contact's presence status is unknown in Teams
• User presence status issues in Outlook

Answer 2

Hi @Ashwini Raman,

Welcome to Microsoft Q&A forum.   

Thank you for reaching out to us. I understand how concerning it is when your Teams contacts suddenly appear as “unknown” and you’re unable to send messages.

We’re aware of a Teams messaging incident that occurred Dec 19–20, 2025 (ID: TM1200517), which caused global delays and unusual presence behavior. If your tenant still has follow‑on impact, that may explain the failed messages.

• You can visit the Microsoft 365 Service Health page or ask your admin to review the Service health dashboard in the Microsoft 365 admin center for any ongoing Teams issues.

In the meantime, here are suggestions you can try to fix it:

1. Try Teams on the web

Go to https://teams.microsoft.com/ and try sending a message and viewing presence.

• If the web client works but the desktop app shows “Unknown” for everyone, it’s very likely a local cache/profile issue on the device.

2. Sign out everywhere, then sign back in

• In the desktop app: Profile avatar → Sign out, then fully quit Teams (including the tray icon).
• Sign out of Teams mobile as well if it’s using the same work account.
• Sign back in to the correct work tenant. This refresh often clears token/profile issues that present as “Unknown” presence.

 

3. Clear the Teams cache

For Windows: 

• If Teams is still running, right-click the Teams icon on the taskbar, and then select Quit.  
• Pressing Windows+R to open the Run dialog box.  
• In the Run dialog box, enter the following path, and then select OK.  

%userprofile%\appdata\local\Packages\MSTeams_8wekyb3d8bbwe\LocalCache\Microsoft\MSTeams 

• Delete all files and folders in the directory.  
• Restart Teams.  

For macOS: 

• If Teams is still running, right-click the Teams icon in the dock, and then select Quit or press Command+Q.  
• In the Finder, open the /Applications/Utilities folder, and then double-click Terminal.  
• Enter the following commands, and press Return after each command:  

rm -rf ~/Library/Group Containers/UBF8T346G9.com.microsoft.teams 

rm -rf ~/Library/Containers/com.microsoft.teams2 

• Restart Teams.

I hope this information is helpful. Please follow these steps and let me know if it works for you. If not, we can work together to resolve this.    

Thank you for your patience and your understanding. If you have any questions or need further assistance, please feel free to share them in the comments on this post so I can continue to support you. 

I look forward to your thoughts on this. 

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