Hello Vapi Team, We are currently blocked in production and would really appreciate urgent assistance. Issue Summary All outbound calls fail immediately with: call.start.error-get-transport Couldn't Create Twilio Call. Twilio Error: Authenticate This prevents any call from being created. 📌 Call Details Failing Call ID: 019c8601-cfaa-7aa5-a73f-15c56d45f1a2 019c85cc-8cfa-7772-af2a-955171c83699 Environment: Production (client account) Twilio Number: Bulgarian number configured in Twilio and registered in Vapi ✅ Expected Behavior The call should initiate successfully via Twilio and connect to the recipient. ❌ Actual Behavior The call fails immediately with a Twilio authentication error and does not reach the customer. What We Have Verified Twilio Account SID is configured in Vapi Auth Token is entered in Vapi The phone number is active in Twilio The phone number is registered correctly in Vapi No credentials were intentionally rotated The issue occurs consistently on every call attempt **Could You Please Verify Is Vapi using the correct Twilio Account SID? If the number is inside a Twilio subaccount, does Vapi require the Subaccount SID + Auth Token instead of the parent account? Were credentials possibly invalidated or rotated? Is there any transport or region restriction affecting Bulgarian numbers? Is there any known Twilio integration issue currently affecting call creation? Impact We have been working on this integration for over 2 months and are now blocked in production. This is affecting a paying client and preventing outbound operations. We would sincerely appreciate prioritization or guidance on how to resolve this as soon as possible. Thank you very much for your support. Best regards, Bozhidar Donchev #1211483291191083018 #Bug #1228667357849849856 🙏 https://cdn.discordapp.com/attachments/1476137449032777870/1476137449230045334/image.png?ex=69a007a1&is=699eb621&hm=4f6c8d58c3a88b3d99556a925d3938a27906f1c927e116f571367c3077b485f8&

Action Step: If your Twilio number is inside a subaccount, ensure you are entering the Subaccount SID and its Auth Token (not the parent account's) in the Vapi dashboard: 1. In Twilio, go to Account > Subaccounts and select the relevant subaccount. 2. Copy the Account SID and Auth Token from the subaccount's API keys & tokens section. 3. In Vapi, re-enter these credentials when importing or editing your Twilio number. This step is critical, as using the parent account's credentials for a subaccount number will cause authentication errors ([Vapi Twilio Import Guide](https://docs.vapi.ai/phone-numbers/import-twilio)). Source: - [Vapi Twilio Import Guide](https://docs.vapi.ai/phone-numbers/import-twilio)

It looks like the Bulgarian number may be in a Twilio subaccount, so Vapi needs the Subaccount SID + Auth Token instead of the parent credentials. Also, double-check the Auth Token wasn’t regenerated. Try re-pasting the exact credentials and test a call directly in Twilio. Can you confirm the DID is in a subaccount and Vapi is using those credentials? @Bobby ^_^

Thank you @James Christopher Just check there are no existing subaccounts the account is brand new, so we have only communicated with the support team via email and they have manually added the parent credentials. I tried to check from Side bar->Phone number but dont see the credentials that are been passed on my end. The origianl problem was that Twilio passed us phone number with one extra number for Bulgaria and they clamed that that is the standart. From my understand since we dont have subaccount credentials it should use only the parent or no?

thanks for the empathetic message @Bobby ^_^ I'm pinging my team to give you an answer

Hey there, You will have to use subaccount ID + Auth token instead of the parent account's credentials; that's the reason for 401. The current account SID being used is AC0034****9663. Please try to use the subaccount ID and the auth token.

ohh ok so now the action plan is to make a subaccount and pass you guys the credentials because currently this was the problem due to the large number count of the phone number ( + 1) I wasnt able to pass the in your UI the credentials in order to integrate the Twilio credentials? I am asking because with my other test accounts I use US number and I never needed a subaccount at least on UI lvl, so not sure why is your achitecture build different as per the other cases, but again I am not sure I can try to pass the phone number sid and token by myself so I will probably need to pass it to you guys, is that ok?

did you manage to fix this ?

Hey, no the ticket is in twilio, at the moment, however they updated part of their required details and now I just tested it again unfortunatelly now I dont see any logs from your system in the call logs and in the webhook logs everything seems to be passing, yet again no call, so can you please send me logs from this ID: 019d1a11-5593-7ff9-b0b0-b855355cd0e4 so i can try to help twilio investigate it further on their part @kyle https://cdn.discordapp.com/attachments/1476137449032777870/1485575069710417970/image.png?ex=69c25d19&is=69c10b99&hm=0f42d692d93a2149f97e8642333e8ef7acb58242b99fd7e76c60e2fd09433f30& https://cdn.discordapp.com/attachments/1476137449032777870/1485575070062743562/image.png?ex=69c25d19&is=69c10b99&hm=51778c8ef16e9dd3967c75e2a3597d8be8094dd45f0f053d13fc00c8217d2a29&