# 30751: Brand Registration Failure: Unsupported mobile phone number

Log Type: APPLICATION

Log Level: ERROR

## Description

This error occurs when you submit an unsupported mobile phone number for A2P 10DLC Sole Proprietor brand registration. Use a supported wireless mobile number for OTP verification before you resubmit the brand registration.

### Possible causes

* The `mobile_phone_number` submitted for the brand does not meet the requirements for Sole Proprietor OTP verification. Twilio sends the verification request to that number as part of the registration flow.
* The mobile number cannot receive the verification SMS needed to complete brand verification.
* The mobile number was acquired from a CPaaS provider such as Twilio, which is not supported for this verification step.

### Possible solutions

* Replace `mobile_phone_number` with a supported wireless mobile number that can receive the verification SMS for brand registration.
* Confirm that the owner of the mobile number can receive the OTP and reply to complete verification. If the OTP expires after 24 hours, trigger a new verification request and complete the reply flow.
* Review the Sole Proprietor registration requirements for the mobile number, update the brand registration details, and resubmit after the number meets those requirements.

#### Additional resources

* [Required Business Information for A2P 10DLC](/docs/messaging/compliance/a2p-10dlc/collect-business-info)
* [Direct Sole Proprietor Registration Overview](/docs/messaging/compliance/a2p-10dlc/direct-sole-proprietor-registration-overview)
* [Troubleshooting Sole Proprietor Brand Registration Failures](/docs/messaging/compliance/a2p-10dlc/troubleshooting-a2p-brands/troubleshooting-sole-proprietor-brand-registration-failures)