I'm curious if anyone has a good idea about this UC320W problem. Cisco phone support already failed.
The problem is this. Incoming SIP callers, when transferred to any extension's voicemail, get silence. No voicemail greeting -- nothing at all. When the call disconnects, the user receives a voicemail notification for a new message but the actual recorded message is missing (or perhaps zero seconds long). This only affects voicemail. The auto attendant works fine. Extensions ring and pick up just fine. It doesn't matter how the caller was transferred to voicemail, human or auto attendant, the voicemail greeting won't play.
Incoming calls via an FXO line work fine. They can be transferred to voicemail, hear a greeting, and record a message successfully.
Internal calls work just fine too. Again, they can be transferred to voicemail, hear a greeting, and record a message successfully.
Only incoming SIP calls have this problem.
The UC320W firmware version is 2.3.2(6) with an NTP PMF. Cisco support tried some sort of PMF and also tried downgrading to version 2.2.2. No luck. We haven't yet tried a factory reset and restore from backup -- that's probably next. We REALLY don't want to try rebuilding the configuration by hand -- an aweful lot of work went into the current configuration.
Any suggestions are welcome.
We have another customer who had exactly the same issue with Sonicwall firewall. I am not familier with it. But I did a brief search at google.com and think you may need to enable SIP Transformations. Please check the following link: