Fixes / Teams · Checked

Teams "We're sorry, we couldn't connect you": causes and fixes

Short answer

Teams shows "We're sorry, we couldn't connect you" when a call or meeting starts but the audio and video link to Microsoft's servers can't be set up. A VPN, firewall or antivirus that blocks Teams media traffic (UDP) is the usual cause. First disconnect the VPN and try the call again. If that doesn't work, quit Teams fully, clear its cache and sign back in.

What this message means

The message appears in the Teams desktop app when you start, answer or join a call or meeting and the connection fails, sometimes right after it starts ringing. You are signed in and chat works, so this is not a sign-in error. The part that fails is the real-time media connection that carries audio and video. Teams needs outbound UDP traffic to Microsoft's media servers for this, and it can be blocked by a VPN, firewall, proxy or security software. It can also fail because of damaged local cache files or an audio device that Teams can't open. A common sign is that the same meeting works in a web browser but not in the desktop app.

Common causes

CauseHow to tell
A VPN is routing or blocking Teams media trafficThe error only happens while your VPN (for example Cisco AnyConnect or GlobalProtect) is connected, and calls work once you disconnect. Colleagues on the same VPN may be fine if their VPN profile is set up differently.
A firewall, proxy or antivirus blocks outbound UDP ports 3478 to 3481Chat, files and presence work, but every call and meeting fails. It often happens only on one network (office, hotel, school Wi-Fi) and works on a phone hotspot.
Corrupted Teams cache or a stale sign-in sessionThe problem started without any network change, happens on every network, and joining the same meeting at teams.microsoft.com in a browser works.
The selected microphone, speaker or headset can't be openedThe failure started after connecting, switching or unpairing a Bluetooth or USB headset or a docking station. Calls connect again when you pick the built-in speakers and microphone.
An outdated Teams appSettings > About Teams shows an old version, you are still on classic Teams, or Teams shows a banner asking you to update or restart.
For direct calls only: the problem is on the other person's sideYou see the message when you call one particular person, but calls to others and group or meeting calls work. The person you're calling may get a missed call, or nothing at all.

How to fix it

1. Test without the VPN and on another network

  1. Disconnect your VPN client, or pause it if your organization allows that.
  2. Quit Teams completely: right-click the Teams icon in the taskbar (Windows) or Dock (Mac) and select Quit.
  3. Open Teams again and retry the call or meeting.
  4. If it still fails, connect the computer to a phone hotspot and try again. If it works there, the original network is blocking Teams media.
  5. If you need the VPN for work, ask IT to set up split tunneling so Microsoft 365 and Teams traffic bypasses the VPN, which is what Microsoft recommends.

2. Join from the browser to narrow it down

  1. Open Microsoft Edge or Google Chrome and go to teams.microsoft.com.
  2. Sign in with the same work, school or personal account.
  3. Join the same meeting or place the same call from the browser.
  4. If it works in the browser but not in the app, the problem is in the desktop app. Continue with the cache and reset fixes below.
  5. If it also fails in the browser, the problem is the network, VPN or firewall. Go back to the first fix or the firewall fix.

3. Switch audio devices and sign out, then back in

  1. In Teams, select Settings and more (...) next to your profile picture, then Settings > Devices.
  2. Under Audio devices, pick the computer's built-in speakers and microphone instead of a Bluetooth or USB headset.
  3. Select your profile picture and choose Sign out.
  4. Quit Teams, open it again and sign back in.
  5. Retry the call. If it connects, switch back to your headset in Settings > Devices.

4. Reset or clear the cache of new Teams on Windows

New Teams on Windows 10 and Windows 11

  1. Type settings in the Start search box and open the Settings app.
  2. Go to Apps > Installed apps and type Microsoft Teams in the search box.
  3. Select More options (...) next to Microsoft Teams, then Advanced options.
  4. In the Reset section, select Reset. This deletes app data and personal settings. You will need to sign in again.
  5. If Reset isn't available, quit Teams, press Windows key + R, enter %userprofile%\appdata\local\Packages\MSTeams_8wekyb3d8bbwe\LocalCache\Microsoft\MSTeams, delete everything in that folder, and restart Teams.
  6. For classic Teams, delete everything in %appdata%\Microsoft\Teams instead.

5. Clear the Teams cache on Mac

New Teams on macOS

  1. Quit Teams by pressing Command (⌘)-Q, or right-click its Dock icon and choose Quit.
  2. In Finder, open /Applications/Utilities and double-click Terminal.
  3. Type rm -rf ~/Library/Group\ Containers/UBF8T346G9.com.microsoft.teams and press Return.
  4. Type rm -rf ~/Library/Containers/com.microsoft.teams2 and press Return.
  5. Open Teams again and sign in. The first start takes longer while the cache is rebuilt. For classic Teams, the folder to remove is ~/Library/Application Support/Microsoft/Teams.

6. Allow Teams through the firewall and security software (IT admins)

  1. Turn off third-party antivirus or firewall web protection for a short test. If calls then connect, add an exception for Teams (ms-teams.exe on Windows, Microsoft Teams.app on Mac).
  2. On the network firewall, allow outbound UDP 3478, 3479, 3480 and 3481 to Microsoft's Teams media IP ranges, as listed in Microsoft 365 URLs and IP address ranges.
  3. Don't send Teams media through SSL inspection or a proxy that only handles TCP.
  4. Make sure the firewall keeps UDP NAT mappings stable during a session, and that the NAT pool is big enough to avoid port exhaustion.
  5. Update Teams (Settings and more (...) > Settings > About Teams) and retry.

Next time, skip the search

Crade is an AI assistant for Mac and Windows that sees your screen. When a message like this pops up, ask “what does this mean?” and it explains the exact error in front of you, step by step.

Download Crade

Still not fixed?

If the error still appears after testing without the VPN, on another network and in the browser, the block is probably a company network or security policy you can't change yourself. Send your IT or help desk the time of the failed call, whether it worked in the browser and on a hotspot, and your Teams version from Settings > About Teams. Admins can look up the failed session in the Teams admin center (Users > the user > Meetings & calls) or the Call Quality Dashboard. If you use Teams with a personal account and have no IT department, contact Microsoft Support through the Get Help app on Windows or support.microsoft.com.

Questions people ask

Why does Teams say "we couldn't connect you" when someone calls me?

The call signal reached Teams, but the media connection for audio and video failed, usually on the side that has a VPN, firewall or broken audio device. If only direct calls to you fail while group calls work, check your VPN and audio device, then clear your Teams cache.

Why does the meeting work in the browser but not in the Teams app?

The browser and the desktop app use separate cache, sign-in and device settings. If the browser works, reset or clear the cache of the desktop app and check its audio devices under Settings > Devices.

Can a VPN cause "Sorry, we couldn't connect you" in Teams?

Yes, it's one of the most common causes. Many VPNs don't handle the UDP traffic Teams uses for calls well, or don't pass it at all, so Microsoft recommends split tunneling so Teams traffic bypasses the VPN.

Will clearing the Teams cache delete my chats or files?

No. Chats, files and meetings are stored in Microsoft 365, not in the cache. You have to sign in again, and a Reset on Windows also removes personal app settings such as theme and notification preferences.

Which ports does Teams need for calls?

Teams needs outbound UDP 3478 to 3481 for audio, video and screen sharing, plus TCP 443 for everything else. No inbound ports have to be opened.

Sources

Related errors