Internal DN to Voicemail not working

[CJ8023]

HI all, I'm facing a situation where internal calls from extension or dn to another internal user transfer the calling user to attempt to sign in instead of directing that user to the called user mailbox? So basically, A calls B, B doesn't answer, transfer to VM, auto attendant receives the call and attempts to sign in A to their own mailbox instead of taking a message for B. 

Any ideas, tips or references are appreciated.

[Gregory Brunn]

SIP Trunk?

If so check your redirecting diversion header delivery - inbound make sure you have it checked both ways In and out.

If not that use port monitor in RTMT to see what the actual values being sent it.  Then check you don't have a forwarding or direct routing rule messing you up.

Also check you make sure the voicemail exist and is there first.

[CJ8023]

Thanks for the reply.

Redirecting Diversion Header Delivery - What should I be looking for, or could you give me an example please?

RTMT - Do I find this in Unified Serviceability or other location? 

Did you mean check to see that the voice mailbox or user is there first? 

[Jaime Valencia]

You were provided with the SIP integration guide in your other thread

https://supportforums.cisco.com/t5/ip-telephony/internal-dn-to-voicemail-not-working/m-p/3204495#M352560

That guide contains what Gregory is referring to, did you review the guide and compared to your current configuration???