WMI polling does not work?

Hi, I am currently running Raspbx with recently upgraded voicemail module (

I had MWI working perfectly well - ie MWI comes on as soon as a message is left and goes off as soon as the message is deleted.

However, I think after the voicemail module upgrade (I think but not 100% sure), the MWI light comes on only after the endpoint (Cisco7960s and Cisco7970s) sends a SIP Register Request after the expiry of the registration and the MWI goes off only after the endpoint sends another SIP Register Request.

To work around I had to reduce the SIP registration expiry time to a smaller value.

It appears the MWI polling does not work although I have made sure the polling is turned on and the poll request time is set to 5 secs.

Any suggestions or comments will be greatly appreciated.


This is a forked project of FreePBX and not directly an Asterisk issue as we have no idea what the people over at Raspbx have done.

That’s because when you REGISTER the system is sending you updates on MWI. Are you sure the device is still set to subscribe/check for MWI? What SIP driver are you using for this endpoint?

@BlazeStudios, thanks for the response and I will try the raspbx forum and see whether someone will be able to shed some light on this.

I am using Cisco7960 and 7970 endpoints and I have not come across any settings to subscribe for MWI in the config files. I presume by default they are which is why it would have been working perfectly OK up until recently. I have been using chan sip all along.

Hi, I ran Wireshark to trace the protocol sequence and observed the following

        Endpoint                          Asterisk

        Register     ------------->        
                                     <-------------       OK
                                     <-------------       NOTIFY

        MWI Off
        Voicemail left
        No changes to MWI

        Register     -------------->      
                                     <--------------      OK
                                     <--------------      NOTIFY

         MWI lights up

         Delete voicemail
         MWI still on

         Register     --------------->    
                                       <---------------    OK
                                       <---------------    NOTIFY

         MWI goes off

To get around for this problem what I have done is to reduce the SIP Register expiry time to 120 seconds. However, a few weeks ago, the MWI responses were almost instantaneous (given the poll time was set to 10 seconds).

I appreciate that since I am using FreePBX on Raspberry Pi (Raspbx) that it might be difficult to guess what the problem is. I am using Chan SIP driver and someone in the Raspbx forum mentioned that PJSIP does not have this issue. I am not having much luck in Raspbx or Freepbx forums and just wondering whether anyone would have any suggestions to resolve this.

Many thanks for your time.

EDIT: running Asterisk 13.24.1