Connection setup of an audio/video chat or SIP softphone call fails. A media connection cannot be established.

Possible reason

The message indicates a problem with the internet/network connection or restrictions due to security settings for the connection between UCServer/UCConnect/ProCall Clients, for example, if they are not on the same network.

Example Scenarios 

This applies for example to: 

  • Mobile clients where softphone calls are to be made via the ProCall Mobile App using mobile data (LTE or similar)
  • ProCall Enterprise clients in the home office that access the UCServer via NAT port forwarding
  • Other scenarios in which the ProCall clients are not directly connected to the UCServer
  • VideoChats via SIP-Federation (with users at other locations/in other company networks)
  • Use of LiveChat for audio/video communication with website visitors

Changes to network or security settings require special expertise and access rights.

Firewall configuration

In order for SIP softphone and audio/video chat to work in the above-mentioned internet scenarios, the following port permissions must be set on the firewall:

  • Direction: Outbound traffic
  • Source-addresses: <All internal addresses> (Concerns in particular: UCServer and ProCall Clients, possibly with DHCP addresses)
  • Source Ports: <All>
  • Target addresses: <Public address of the used TURN server> (when using UCConnect:
  • Destination ports: 3478 and 443
  • Transport types: UDP and TCP

Test in UCServer

The UCServer Admin can be used to test whether the UCServer or the media proxy can establish a connection to the TURN server. The STUN and TURN diagnosis can be found under Services → STUN / TURN.