Unity Connection voice mail for third party PBX

[Mahmoud Al Hasan]

I have Unity connection installed at a customer place and they have NEC , Connection is as below

UNITY CONNECTION <- - - - > SIP < - - - >CUCM < -- -- >SIP < - - - >ACME SBC  < - - - - > SIP < - - - -> NEC PABX

NEC users want a voice mail facility on Unity  connection, users created with extension number on Unity Connection

When receiving a call on NEC and it is being forwarded to CUC I don't get "user is not available, please leave a message"

I get "Welcome to Cisco Unity Connection Messaging system......", which does not make me able to leave a voice message 

While if I call a Cisco phone that is forwarded to CUC I get "user is not available, please leave a message"

Is there a special configuration that needs to be done to be able to leave a message?

Thanks in advace

[Vivek Batra · Accepted solution]

To send the call to user's mail box, INVITE must include redirect diversion header which invokes forward routing rule in CUC to take the call to user's mailbox. Seems it's not included in your case. You can check and verify the same by looking at INVITE headers.

- Vivek

[pwoll]

Thank you for this.  I had the very same problem and this solved it.