THere are the most common reasons the “phone number not found” error shows up when you use Zapier’s Make outbound call action and how to fix them:
• Use the phone-number ID, not the phone number itself – Zapier expects the internal Agent Phone Number ID (a 24-character string such as ).
• Confirm the rest of the credentials:
– Voiceflow Project API Key
– Voiceflow Project ID
– “To” number in E.164 format (e.g. )
• If you added or changed the phone number after first linking Voiceflow to Zapier, click Reconnect on the Voiceflow account step so Zapier refreshes the list of valid phone-number IDs.
After those checks the call should go through (your Twilio settings are already proven by your hard-coded test call).
Docs reference: https://docs.voiceflow.com → Zapier → “Make outbound call – requires an Agent Phone Number ID”.
• Use the phone-number ID, not the phone number itself – Zapier expects the internal Agent Phone Number ID (a 24-character string such as ).
- In Voiceflow open your project → Interfaces → Telephony.
- Click View next to the number you want to call from.
- Copy the ID that appears in the cURL example and paste it into the Agent Phone Number ID field in Zapier.
(Entering here will return phone number not found.)
• Confirm the rest of the credentials:
– Voiceflow Project API Key
– Voiceflow Project ID
– “To” number in E.164 format (e.g. )
• If you added or changed the phone number after first linking Voiceflow to Zapier, click Reconnect on the Voiceflow account step so Zapier refreshes the list of valid phone-number IDs.
After those checks the call should go through (your Twilio settings are already proven by your hard-coded test call).
Docs reference: https://docs.voiceflow.com → Zapier → “Make outbound call – requires an Agent Phone Number ID”.
Voiceflow
Build, manage, and deliver chat and voice agents for customer support and beyond.
TAfter I updated Agent Phone Number ID, Zapier app returned "Unauthorized".
T (HTTP 401) means Voiceflow rejected the request because one of the credentials it received from Zapier is no longer valid.
Here’s what usually fixes it:
Here’s what usually fixes it:
- Verify the Voiceflow connection in Zapier• In the Zap action click “Reconnect” (or “Connect a new account”).• Paste the current **Project API Key** and **Project ID** shown in Voiceflow →
Project Settings → API Keys / General tab.• If you recently regenerated the key or moved the project, the old key stored in Zapier is now invalid and will trigger 401. - Double-check the **Agent Phone Number ID**• Open Voiceflow → Interfaces → Telephony → View next to the phone number you want to call from.• Copy the ID that appears in the cURL example after `/phone-number/` (format `pn_…`). Make sure you grab it from the correct environment (Dev vs Prod) – each environment has its own ID.• Paste this value into the *Agent Phone Number ID* field in your Zap.
- Make sure the phone number is still assigned to the agent (Integrations → Telephony → Phone Numbers) and that the agent was republished after any routing changes.
- Test the Zap again. If the credentials match what Voiceflow shows, the step should return 200 OK.
