Check your Linphone configuration using sipomatic, a small test program that can answer calls made from Linphone.
Procedure 12.2. Testing a Linphone Setup
Open a terminal.
Enter sipomatic at the command line prompt.
sip:email@example.com:5064 as and click .
If Linphone is configured correctly, you will hear a phone ringing and, after a short while, you will hear a short announcement.
If you successfully completed this procedure, you can be sure that your audio setup and the network setup are working. If this test fails, check whether your sound device is correctly configured and whether the playback level is set to a reasonable value. If you still fail to hear anything, check the network setup including the port numbers for SIP and RTP. If any other application or protocol uses the defaults ports for these as proposed by Linphone, consider changing ports and retry.