You may have captured the packets, but they contain a lot more than you have presented. Also, in general, it is much easier for people to use the packet traces from Asterisk, not from third party software, as they are interleaved with other logging information, if captured properly (google “asterisk wiki debug” for more information).
Asterisk will only send things to its voicemail if you have configured it to do so. if it is sending to voicemail, we would need to see your dialplan.
It is not clear whether the summary trace is for the inbound call to Asterisk or the outbound one from it. In the former case, it is probably something upstream of Asterisk that is sending the call to voicemail, and the Asterisk logs should provide more information on why Asterisk is returning number not found.
In the latter you would need to investigate why the system downstream of Asterisk was returning number not found. Knowing the number that was in the INVITE would be rather helpful, which is one reason why the summary isn’t of much use.