PJSIP Trunk failing to Authenticate Outbound

M1kemclain247 · July 7, 2025, 5:33pm

Hi all,

I’m having trouble getting a PJSIP trunk on VitalPBX to successfully authenticate outbound to our SIP provider (TelOne Zimbabwe). Inbound calls work, and SIP registration is attempted, but outbound authentication consistently fails.

Setup Details

PBX: VitalPBX (latest)
Transport: UDP
SIP Domain: ims.telone.co.zw
SIP Server IP: 197.221.224.35
Trunk Username: [email protected]
NAT: Enabled
Auth Username: Same as SIP URI
Registration Interval: 3600s
Outbound Proxy: Tried both blank and sip:ims.telone.co.zw:5060

sngrep Comparison

Working REGISTER from Yeastar PBX:

REGISTER sent to: sip:ims.telone.co.zw:5060;transport=udp
Includes full Authorization: Digest ... header with realm, nonce, qop, etc.
Uses SIP domain in both Request URI and Route headers

Failing REGISTER from VitalPBX:

REGISTER sent to: sip:197.221.224.35:5060
No Authorization header included in initial or follow-up REGISTER
Contact IP is public: sip:[email protected]
Fails on outbound auth even though credentials are correct

What I’ve Tried

Verified SIP credentials and auth username
Changed SIP Server to domain (ims.telone.co.zw) instead of IP
Added outbound proxy
Ensured NAT and transport settings are correct
Compared sngrep output between Yeastar and VitalPBX

It looks like VitalPBX either:

Isn’t responding to the 401 Unauthorized challenge with an Authorization header, or
Isn’t constructing the auth digest correctly due to mismatch in realm or URI