Why does the audio sometimes stop working in the middle of calls in my Amazon Connect contact center?

2 minute read

The audio sometimes stops working when agents in my Amazon Connect contact center are in the middle of a call. Why is this happening, and how do I troubleshoot the issue?

Short description

The Amazon Connect Contact Control Panel (CCP) uses Softphone Media UDP port 3478 to relay audio. If the CCP loses its connection to the Media endpoint with UDP port 3478 during a call, the call's audio stops.

This type of networking issue appears in the Amazon Connect CCP logs as lost connection errors, similar to the following example.

Example CCP log of a lost connection error

2021-09-29T19:46:31.422Z softphone INFO 12345678-90ab-cdef-1234-567890abcdef SESSION Lost ICE connection

To identify lost connections to your Media endpoint specifically, use the CCP Log Parser to turn your raw CCP logs into a more read-friendly format. Then, look at the Metrics section of the CCP Log Parser. A sudden drop in the packetsCount metric in the WebRTC Metrics - audio_input / audio_output section indicates a Media endpoint networking issue.

For more information, see CCP Log Parser in GitHub.


  1. Confirm that nothing is blocking traffic to the Media endpoint with UDP port 3478. For more information, see Replace Amazon EC2 and CloudFront IP range requirements with a domain allow list.
  2. If you're allowing traffic with IP address ranges, then confirm that all IP addresses used by Amazon Connect are on the required allow lists. For more information, see Allow IP address ranges.
  3. Confirm that your network connection is stable enough to allow the CCP to maintain connection with the required endpoints. To validate connectivity to Amazon Connect, use the Amazon Connect Endpoint Test Utility.
  4. Confirm that the agents' workstations meet the minimum requirements for the CCP.

AWS OFFICIALUpdated 2 years ago