We get this error now on all calls: call.in-progress.error-sip-telephony-provider-failed-to-connect-call Any changes done? New ip addresses? What can I check to find the root cause? @Shubham Bajaj

Hi there! Sorry to hear you're experiencing connection issues with all your calls 😕 I don't have information about any recent changes or new IP addresses specifically, but I can definitely help you troubleshoot this "call.in-progress.error-sip-telephony-provider-failed-to-connect-call" error. Here are several potential root causes and things you can check: ### Network & Firewall Configuration - Verify your network allows SIP protocol traffic and that firewalls/NATs are configured to allow SIP messages through - Check if any firewall settings are blocking SIP traffic on relevant ports - Ensure proper IP whitelisting - some users needed to whitelist specific IPs (44.229.228.186 and 44.238.177.138) to resolve similar issues ### SIP Configuration Issues - Check the SIP URI format in the

sipUri

attribute within the

forwardingPhoneNumbers

array - Verify the

forwardingPhoneNumber

is in the correct E.164 format (e.g., +15558675309) - If using a Vici system, confirm it can handle SIP REFER messages ### Authentication Problems - Double-check that credentials provided to Vapi are correct if your SIP endpoint requires authentication - Ensure your SIP provider is sending username/password entries for sip.vapi.ai - When Vapi sends a 401 challenge, the system needs to respond with valid credentials ### Telephony System Issues - Your telephony system might not be responding in the required time - Check telephony logs to investigate further - Verify that your SIP server or PBX is configured to accept calls from Vapi's servers ### Other Potential Causes - Codec compatibility issues (ensure codecs used by Vapi are supported by your SIP endpoint) - Database outages (e.g., with Supabase) - Concurrency limits being exceeded - SIP trunk configuration problems - Incorrect SIP registration - Issues with call transfers or call forwarding ### Troubleshooting Steps 1. Check server and telephony logs for specific error details 2. Verify your internet connection is stable

Same thing is happening to me. My phone call connection was fine yesterday and days before that but today im unable to call through to my vapi number via my phone which was strange as its only happening today.

The SIP server has been down since yesterday, and I'm getting SIP trunk UNREACHABLE messages from several PBXs. Can Support look into this urgently? @User

+1

+1

+1

This is started recently. Previously, we resolved it, but we didn't close the incident as it was under monitoring, so it came again today. It's all when we have an unexpected amount of calls on the network, this comes up. Currently, we are doing what we can to upgrade everything so that this never shows up again

Totally understand that you're working on this. This seems like a pretty important issue to resolve. Few questions that might help us: - Do you expect this to happen again in the future? - Does this issue only impact Vapi phone numbers? Or all incoming/outgoing calls even via Twilio etc?

This issue basically originates from our SIP stack, not from the core VAPI itself. We don't expect this to happen again in the future, and it has affected all of the SIP calls. For now, we are doing an RCA first that will evaluate other options for our SIP stack, and then we'll choose a better mode for it. A stable stack within a win for it.

+1

Hey guys, please try now. This issue has been resolved, and SIP calls must be working for you.

+1

We still get the same error throughout the entire day. @Shubham Bajaj Call IDs: b3f056f6-9fb7-4810-a822-785bd709ed67 f1410c77-6b8d-4c4e-82dd-08a7fdbd4695 e26f0b39-660d-4ba4-b2e2-0e4d794ca2f0 and many more. An error occurred in this call: call.in-progress.error-sip-telephony-provider-failed-to-connect-call

looking into it.

Hello eveyone, I am also geetting this error constantly. Call ids: a9e2dde7-537b-4535-b632-39286b5d2bdb 07fd693f-9656-4424-b1a4-4cd3bbd818bc Has anyone solved it yet?

Hi, checking if this is resolved/solved for you?

@Shubham Bajaj this is still happening all the time for me

same with me here @Shubham Bajaj

🔵 22:08:58:307 Processing

phoneNumber

Deletion... { "id": "70e63263-ea00-4824-9672-d4a803f87d7a", @pabl0ro Can you share a call ID with whose phone number is not deleted?

@Shubham Bajaj 13c7d5dc-3465-462d-8351-3a7f44c07f2b 651b783c-aab7-4385-b2ea-1a475bb81750 767403d6-6673-4410-afc4-a3a281f29d13 c2ae0767-e1d6-4681-b2bb-5d3e01535d4e a26597e6-8a7f-4f82-a5b9-ae491da7b8ed

looking into it.

still getting a lot of "call.in-progress.error-sip-telephony-provider-failed-to-connect-call" errors

Hello Vapi Team. I am getting this error also. Few days ago it worked all fine. But today not anymore. Here is my call ID : 4a061fe3-c896-4f36-b21a-71a14d8ee93a Ple And if you have more insights on why it is not working would be very helpfull.

ok thanks a lot!

Nice

@Shubham Bajaj : here is a call I just tried c1b233fc-1ebf-4815-a52a-fbaa7244576b no matter how much I tried, no luck

This ticket has been marked as solved, and as a result, you will no longer receive any further responses. Kindly create a new support ticket to escalate your inquiry. 

Hi @Shubham Bajaj I am trying to make outbound call using VAPI and Plivo (I have purchased indian number and destination number is also indian) { "id": "0f1c1751-c734-424f-89ef-15200963ba9a", "assistantId": "52739d19-cdce-4903-8563-a1476d2d0d39", "phoneNumberId": "ba4e0f4e-fe1e-444d-b715-638e71703230", "type": "outboundPhoneCall", "createdAt": "2025-05-06T02:59:39.799Z", "updatedAt": "2025-05-06T02:59:39.799Z", "orgId": "a55e28be-be19-4ff3-bb9a-d2aae6511e42", "cost": 0, "customer": { "number": "+917814064561", "numberE164CheckEnabled": false }, "status": "queued", "phoneCallProvider": "vapi", "phoneCallProviderId": "141cb4ce-a6ba-4071-b639-f0fce8089f01", "phoneCallTransport": "pstn", "phoneCallProviderDetails": { "sbcCallId": "fe45f893-a4c8-123e-4fbb-06496812ecbf" }, "monitor": { "listenUrl": "wss://phone-call-websocket.aws-us-west-2-backend-production2.vapi.ai/0f1c1751-c734-424f-89ef-15200963ba9a/listen", "controlUrl": "https://phone-call-websocket.aws-us-west-2-backend-production2.vapi.ai/0f1c1751-c734-424f-89ef-15200963ba9a/control" } } here is the response of call/phone api endpoint. getting this error An error occurred in this call: call.in-progress.error-sip-telephony-provider-failed-to-connect-call Please help me

Hey Madhav, please create a new support ticket for your issue. This ticket has been closed, so you won't be getting any support help here.