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
65be7d7d1ae227bf482bb2c6).- 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+1-xxx-xxx-xxxxhere 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.
+15551234567)• 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".
TUnauthorized (HTTP 401) means Voiceflow rejected the request because one of the credentials it received from Zapier is no longer valid.Here’s what usually fixes it:
- 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.
