Hi! I have an issue with inbound BYO SIP Trunking. My carrier (Inbtel/PBXHosting, Sippy Softswitch) sends INVITEs from IP 207.182.145.2 to sip:526627760699@sip.vapi.ai:5060 but Vapi always responds 401 Unauthorized (Digest challenge). The carrier operates in IP-auth mode only and cannot respond to Digest challenges. What I already configured: BYO SIP Trunk credential with IP 207.182.145.2, inboundEnabled=true (ID: 8516b872-087a-48ee-a1b0-c75c91413fe0) SIP URI phone number sip:526627760699@sip.vapi.ai (ID: 57ac14e5-e307-4ef4-b441-f9383a5a2794) The problem: Vapi still sends 401 Unauthorized on every inbound INVITE. I have a PCAP proving the traffic reaches Vapi correctly. org ID: c72786ec-d64f-4f80-a79a-c47f504a73c2 Can you help enable IP-auth (trusted peer, no Digest) for inbound INVITEs from 207.182.145.2 for this org? https://cdn.discordapp.com/attachments/1502458171229470811/1502458171501973504/401_526627760699.pcap?ex=69ffc8b6&is=69fe7736&hm=920ae155866c5eda9510b27920808856149b7d5af4c4bb1d331c195cf327ad58& https://cdn.discordapp.com/attachments/1502458171229470811/1502458171955089589/dump_1_166.pcap?ex=69ffc8b6&is=69fe7736&hm=f4ac08a2f8456a43098e37d55f94aaefa69ee7f9d0a68f9ac63aba69328c3f04&

Hey, @Saul this is a known friction point with Vapi's BYO SIP trunking when the carrier is IP-auth only. The 401 loop happens because Vapi defaults to Digest challenge even when a trusted peer IP is configured, and there's a backend flag needed to bypass that for your org. I can get this sorted for you directly. Quick question: is the INVITE hitting sip.vapi.ai on port 5060 with the full DID in the Request-URI, or is the carrier sending it to a different format?

Hi Matt! Thanks for the quick response. Yes, the INVITE is hitting sip.vapi.ai on port 5060 UDP with the full DID in the Request-URI: INVITE sip:526627760699@sip.vapi.ai:5060 SIP/2.0 The carrier (Sippy Softswitch) sends it from 207.182.145.2:5060. Vapi responds 401, then the carrier retries directly to the resolved IP 44.238.177.138:5060 (same Request-URI user 526627760699) and Vapi responds 200 OK but sends a BYE after ~1.5 seconds. So the INVITE format is correct — the issue is purely the 401 on the FQDN and the premature BYE on the IP retry. Please go ahead and set that backend flag for our org. org ID: c72786ec-d64f-4f80-a79a-c47f504a73c2 Credential ID: 8516b872-087a-48ee-a1b0-c75c91413fe0 Phone Number ID: 57ac14e5-e307-4ef4-b441-f9383a5a2794 Trusted peer IP: 207.182.145.2

If inbound routing is configured, call your phone number from an external line. Ensure your provider forwards calls to the correct SIP URI:

{phoneNumber}@<credential_id>.sip.vapi.ai