Question

Why are my Programmable Voice test calls failing with 401 errors on my new trial account?

Product

Programmable Voice

Environment

Twilio Console

Answer

When you first sign up for a Twilio trial account, you are prompted to provide a personal phone number, which becomes your verified caller ID. Twilio then automatically pairs this verified caller ID with a specific Trial Number. You do not need to buy or acquire a new Twilio number to start testing.

To find your pre-assigned testing numbers and successfully place outbound calls:

1. Log in to the Twilio Console.
2. From the left navigation or main landing page, go to Home Page > Dashboard > Voice.
3. Click on Try Out Voice.

Under this section, you will see the only valid phone number combination permitted for your trial account testing:

• From Number: The specific trial number Twilio automatically assigned to you.
• To Number: The personal verified caller ID you provided during sign-up.

Important: Your outbound test calls or API scripts must use this exact pairing. Attempting to use an unassigned number, or calling any destination other than your initial sign-up number, will result in policy evaluation failures (401 errors) or the error message: "from number isn't assigned to this verified voice recipient."

Additional Information 

• Console Behavior: Attempting to manually purchase phone numbers or add new verified caller IDs through the standard phone number management pages will trigger prompts asking you to upgrade your account. For trial testing, rely strictly on the numbers shown in the Try Out Voice dashboard.
• Removing Restrictions: If you need to test outbound calls to other numbers or use different Twilio phone numbers, you must upgrade your trial account to a full production account by adding a valid payment method.