Audio problem with Asterisk 11.2.0

Dear all,

i have updated one server with Asterisk 11.2.0. After the update, i started to have some problems regarding audio during conversation.
Some extensions when they call external numbers and also sometimes other extensions, the caller (that is a sip peer) listen correctly the audio while the called doesn’t listen the audio.

What can be the problem? Can you help me to debug the problem?

Thank you very much!

Firewall or NAT.

You need to provide network topology information, sip.conf contents, and the SDP from the the SIP INVITEs.