Hi Pat, Thanks — this error usually means the SDK request's phoneNumberId doesn't match the ID Vapi expects (even if it appears in the dashboard). Please try the following checks: 1. Confirm you're passing the phone number resource ID (not the raw E.164 number). Use the exact "id" shown in the dashboard for that phone number. 2. Ensure the token you use with the SDK is for the same org that owns the phone number. 3. If using environment variables, confirm there are no stray characters or braces around the ID (e.g., no quotes, newline). 4. Reproduce with the SDK example from the docs and the dashboard id: • Python: client.calls.create({ "phoneNumberId": "ID_FROM_DASHBOARD", ... }) • Typescript/Go examples are in the docs for reference. Link: https://docs.vapi.ai/calls/outbound-calling 5. If you still see the 400, run one more check: call the phone-numbers.get endpoint for that id via the SDK to confirm it returns the resource (examples: https://docs.vapi.ai/api-reference/phone-numbers/get). If you share: • The exact SDK call (with the id redacted) and • The org token used, I can point out any mismatch quickly.