Hi team, I have three DIDs configured in my account using the same credential: • 1435009594 • 4825000594 • 3525000103 Inbound calling works normally for the first two DIDs, however when I call 3525000103 I get an audio message saying: “phone number not found”. I already checked the SIP INVITE and confirmed the headers and formatting match the working DIDs — everything is following the same pattern/standard. I need to understand why DID 3525000103 is returning this message. I’ve performed multiple tests but still couldn’t identify the root cause. This is urgent — please assist as soon as possible. OrganizationID: 70efdbde-85ab-41b9-a671-2d207484a03d Thanks

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Hi I’ve seen this exact “number not found” behavior before, and it’s usually not SIP formatting but a routing or DID-level association issue on the provider side. Even when credentials are shared, one DID can silently miss an inbound route, destination, or be stuck in a pending/provisioning state. I can help you quickly narrow this down by checking DID binding, inbound trunk mapping, and carrier lookup behavior. One key question: is 3525000103 definitely assigned to the same inbound application/trunk as the other two in the portal (not just via credentials)? If you’d like, we can jump in and debug this end-to-end to get it resolved fast. @andmac

Hi @Jarrah ! Thanks for helping. Yes, confirming 3525000103 is assigned to the same inbound SIP trunk/credential as the other two working DIDs. I’m attaching two screenshots: 1. GET /credential showing the trunk credential + gateways 2. GET /phone-number showing all 3 DIDs pointing to the same credentialId (and all status: active) So trunk/credential binding looks consistent. Since only 3525000103 returns “phone number not found”, this seems like a DID-level routing/provisioning issue rather than SIP formatting. Any ideas on what else I can check from my side, or any additional info/logs that would help narrow this down? https://cdn.discordapp.com/attachments/1459556488593932319/1460253746134257684/image.png?ex=69663ec7&is=6964ed47&hm=e609cc28a085970dc0384ad5bea965532427c8be74fd75ad204c23c292467603& https://cdn.discordapp.com/attachments/1459556488593932319/1460253747102875670/image.png?ex=69663ec7&is=6964ed47&hm=a1913ae8638a2e129ffb89b648e1c99dbe5bb58a52af01f5ef077c43d0ef48ef&

Great screenshots that rules out 90% of the usual causes 👍 Given all three DIDs are active and bound to the same credential, this strongly points to a carrier-side DID routing table issue (often the DID exists in inventory but isn’t fully mapped to the ingress gateway). SIP won’t even hit your trunk in that case, which explains the generic “number not found” audio. From your side, the only meaningful checks left are: confirm whether any INVITE at all is generated for 3525000103, and compare the providerResourceId / carrier reference for that DID vs the working ones. I’ve helped debug this exact failure mode before (silent carrier mis-provisioning, region gateway mismatch, stale routing cache). If you want, we can look at it privately and get it resolved quickly without the back-and-forth. @andmac

Hi @Jarrah , thanks for the help. I’ll DM you so we can debug this quickly.

Hey! we're looking into this for you and will follow up soon

Hi, Quick update with additional context. Regarding the earlier question: I’m calling this DID from Brazil, so I dial it as a Brazil local fixed-line format: (35) 2500-0103 (no “+1”). It’s possible that calling tel:+13525000103 is reaching a different route/number. Also, based on my SIP traces (INVITE → 100 Trying → 200 OK → ACK), the call is definitely reaching Vapi and being accepted, but I still hear the “phone number not found” audio message only for DID 3525000103. On my side I already: • Deleted and recreated the SIP credentials/trunk • Removed and re-added / re-assigned the phone numbers multiple times • Confirmed all three DIDs use the same credentialId and gateways, and SIP headers match the working DIDs Despite all of this, the issue persists only for 3525000103. Could you please investigate what’s happening for this specific DID on Vapi’s side? OrganizationID: 70efdbde-85ab-41b9-a671-2d207484a03d Thanks

Hi Andre, could you send the request to the following sipURI: sip:+13525000103@sip.vapi.ai, test it, and let me know how it goes?

The problem happens when this DID is dialed from Brazil as a local fixed-line number: (35) 2500-0103 (no “+1”). Dialing +1 352 500 0103 forces an international/E.164 route and may reach a different path/normalization, so it’s not equivalent to the failing scenario. From my SIP traces, the call is reaching Vapi and being accepted (INVITE → 200 OK), but Vapi still plays “phone number not found” only for this DID. At this point, I strongly suspect this is a Vapi-side routing/provisioning issue specific to this DID (carrier mapping / DID routing table / normalization mismatch) rather than anything on my SIP trunk configuration. As a next step, I’ll add another phone number in the same area code and test inbound calls to compare behavior.

Was going through the code and your hypothesis seems correct. We convert the number

3525000103

to E.164 format and return it even when

numberE164CheckEnabled

is set to

false

. This happens because the

usernameToE164

check runs first and returns early, so the

numberE164CheckEnabled

condition never gets reached. I need to double-check with the product teama about it and it might take sometime to go through it and make the necessary changes.

Understood, thanks for confirming. I’ll wait for your update after you check with the product team. One additional data point: it’s strange because my other two DIDs follow the exact same flow and work fine, this issue seems specific to this DID. Re: SIP to my domain: that’s intentional for debugging (I keep the DID pointed to my SIP domain and forward upstream as needed). Is there any issue with this approach? I’m currently allowing only one Vapi SIP IP. Also, I tested pointing the DID directly to sip.vapi.ai (bypassing my domain) and the issue still happens, so I don’t think the domain forwarding is the cause.

Andre, can you try to create the number once again and see if you still seeing this issue or not?

Hi Sahil, I redid the whole setup from scratch to confirm. What I did: • Deleted all existing phone-numbers • Recreated the SIP credential • Recreated the DIDs again with the new credential Results: • 4825000594 — works fine • 3525000103 — still gets “Phone number not found” Additional test: I also acquired a new DID from my provider and repeated the full process: • 3525000104 — also gets “Phone number not found” So it looks like any DID in this 352 range is failing, while the 48 DID works normally, and I specifically need the 35 DID working for this customer. Let me know what you find on your side.

Thank you for trying, can you setup that number in staging so that I can debug in local and figure out more about this issue? You can create an account over here and do all the configuration from here https://staging-dashboard.vapi.ai/

Hi! I tried accessing the staging dashboard, but it looks like only vapi.ai domains have access. If you want to simulate the scenario on your side, I can share (privately) the credentials I used and the phone number so you can register it there and test/debug. https://cdn.discordapp.com/attachments/1459556488593932319/1462802368558268501/Screenshot_2026-01-19_at_10.31.49.png?ex=696f845e&is=696e32de&hm=3ba4262669927aee2dabe23fec8fc97938c92592aa77a7e4f042bba7855e7728&

Please do.

I am running into the same issue with phone number not found. Was there a resolution to this issue?

Can you share your call ID or PCAP file?