We can make and receive calls outside the network. When we initiate the call encryption works great. However when someone from outside the network makes a call, encryption will not working. If we set to force encrytption the call does not go through. If we set to Available, the call goes through without encrption. Is there something specific for an asa to pass encrypted traffic? I called support and they gave me a list of ports to open, which are already open.
Sure sounds like something in your firewall is affecting incoming calls requesting/needing encryption. Your outgoing calls with encryption are successful thru the firewall, right?
Logs and/or packet captures might show some clues. Also, posting this on a Cisco Support Community forum might get help.