Microsoft Teams Calls Dropping: How to Fix It

Step 1: Run a packet loss test

Open Command Prompt and run: ping 8.8.8.8 -n 200. Any packet loss causes Teams call drops because Teams uses UDP and cannot recover dropped packets. Even 0.5% loss is enough to cause audible cuts. If you see any dropped packets, fix the network layer before adjusting Teams settings.

Step 2: Switch to wired Ethernet

Teams UDP streams drop on Wi-Fi with more than 0.5% packet loss. Wi-Fi congestion and interference cause bursts of packet loss that immediately manifest as call drops. A wired Ethernet connection eliminates this variability. If cabling is not possible, switch to 5 GHz Wi-Fi and reduce the distance to the router.

Step 3: Check for UDP throttling

Some routers and ISPs throttle or block UDP traffic. Teams uses UDP ports 3478-3481 for media. To test: if Teams audio works but video and screen share drop, UDP is likely being throttled. Check your router's firewall settings for UDP rate limiting and ensure ports 3478-3481 are not blocked outbound.

Step 4: Update Teams client

Some Teams versions have known connection bugs that cause random call drops — these are fixed in subsequent updates. In Teams: click your profile picture > Check for updates. Microsoft releases Teams updates frequently; running an older version can cause drops that have already been patched.

Step 5: Enable QoS for Teams traffic

Quality of Service prioritizes Teams UDP packets over bulk traffic like downloads and streaming. In your router's QoS settings, mark traffic to UDP ports 3478-3481 as high priority. Microsoft recommends DSCP value 46 (Expedited Forwarding) for Teams audio and video. This prevents downloads from crowding out call packets.

Step 6: Enable split tunneling on VPN

If you connect through a work VPN, all Teams traffic may be routed through the VPN tunnel, adding latency and congestion. Enable split tunneling to route Teams traffic directly to Microsoft's servers outside the VPN. Microsoft publishes a list of Teams IP ranges and URLs specifically for split tunneling configuration.

Step 7: Restart Teams and router before important calls

Restarting the Teams app clears its cached server connection and forces a fresh session negotiation. Restarting the router flushes stale NAT entries and UDP state tables. Do both 10 minutes before important calls. If Teams frequently drops on a specific schedule, check router logs for recurring WAN disconnections.

Frequently Asked Questions

Why do Teams calls keep cutting out?

Teams calls cut out due to packet loss on the network path between your device and Microsoft's servers. Because Teams uses UDP (not TCP), there is no automatic retransmission — each lost packet becomes a gap in audio or a freeze in video. Even brief congestion on Wi-Fi or a shared internet connection causes audible cuts. The fix is almost always wired Ethernet plus checking for packet loss with a ping test.

Does Teams work better on wired?

Yes, significantly. Wi-Fi introduces jitter and packet loss that UDP-based media streams cannot tolerate. A wired Ethernet connection typically reduces packet loss to 0% and jitter to under 5 ms, which is well within Teams' tolerance. If call drops disappear immediately after switching to wired, Wi-Fi was the cause.

What ports does Microsoft Teams use?

Microsoft Teams uses UDP ports 3478, 3479, 3480, and 3481 for audio and video media. It also uses TCP port 443 for signaling and control. If your router or ISP throttles UDP on these ports, Teams will fall back to TCP relay which is slower and more prone to dropping. Ensure UDP ports 3478-3481 are open outbound on your firewall.