error when trying to submit the form

Hi,
after filling out the form and trying to submit I receive error:
{“code”: 21212, “message”: “The ‘From’ number CrazyBird School is not a valid phone number, shortcode, or alphanumeric sender ID.”, “more_info”: “https://www.twilio.com/docs/errors/21212”, “status”: 400}

When I remove reference to phone number given by customer in config tab, the form is submitted correctly. I tried with country code and without country code. all plugins are just updated to the newest versions.
Piotr

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