Please can somebody help. I’m testing the 3CX software with Orbtalk (http://www.orbtalk.co.uk) as the SIP provider. I can make and receive calls without problem but there is no audio either direction. I’m receiving the message “Can't send RTP stream to 193.104.xxx.xxx:39592 destination unreachable”. 193.104.xxx.xxx (xxx.xxx replaces origianl ip) is the name of the mediaserver of Orbtalk. I also receive: No RTP packets were received:remoteAddr=193.104.xxx.xxx:38124,extAddr=77.73.xxx.xxx:9000,localAddr=77.73.xxx.xxx:9000 77.73.xxx.xxx (xxx.xxx replaces origianl ip) is the name of my server hosting the 3CX software. To ensure there is no firewall issue, I’ve turned off all firewalls on the service hosting the 3CX software as well as the Windows 7 client making the calls temporarily. I've enabled tracing of the 3CX processes and in the MediaServer.trace.log I see the following error in addition to the above messages: C:1.1: Failed to receive incoming stream from 77.73.xxx.xx:10004 WSAError=10054 Does anybody have any experience of this error or any suggestions to solve it? Thanks in advance, Tony.