You are obfuscating your logs too much. Makes it hard to see what's going on. Leave the IP addresses in.
You are certainly reaching twilio, because you are getting an initial response from them:
The reason I'm asking about your IP is maybe you are sending them a contact header that doesn't get back to your PBX. The Via header I just quoted doesn't tell me whether you are obfuscating a NAT address or a public address. I assume it's public since Twilio puts it in the received= tag but who knows since you changed it all around... Last thought, do you have port 5080 open?
You are certainly reaching twilio, because you are getting an initial response from them:
recv 379 bytes from udp/[54.172.60.1]:5060 at 16:05:58.590510:
------------------------------------------------------------------------
SIP/2.0 100 Giving a try
Via: SIP/2.0/UDP 100.100.100.100:5080;received=100.100.100.100;rport=5080;branch=z9hG4bK2Q5c9pycaSpmS
From: "asdf" <sip:someguy@gmail.com@vursify.pstn.twilio.com>;tag=mDy3SpvNKrvyD
To: <sip:1234567891@vursify.pstn.twilio.com>
Call-ID: 95ca3ee0-a30d-1236-eab1-56000168b138
CSeq: 120228914 INVITE
Server: Twilio Gateway
Content-Length: 0
The reason I'm asking about your IP is maybe you are sending them a contact header that doesn't get back to your PBX. The Via header I just quoted doesn't tell me whether you are obfuscating a NAT address or a public address. I assume it's public since Twilio puts it in the received= tag but who knows since you changed it all around... Last thought, do you have port 5080 open?