MS CRM 2015 Email router processing Voicemails

I have an XXXX@yyyy.com mailbox which is processing all the incoming emails properly to MS CRM queue <XXXX@yyyy.com> using email router.

Now, I have configured a voicemail functionality to one of the phone line, which is sending, if any voicemails left to XXXX@yyyy.com.  I am not able to process these voicemails to CRM queue.

How can I process them in CRM?