---
title: "A2P 10DLC Registration Error"
slug: "a2p-10dlc-registration-error"
description: "Understand why sending of SMS/MMS may fail from phone numbers not registered for A2P 10DLC. Visit Gladly Help Docs to learn more."
updated: 2025-08-22T17:37:21Z
published: 2025-08-22T17:37:21Z
---

> ## Documentation Index
> Fetch the complete documentation index at: https://help.gladly.com/llms.txt
> Use this file to discover all available pages before exploring further.

# A2P 10DLC Registration Error

| **REQUIRED USER ROLE** Administrator | **PERMISSION OVERVIEW** [View permissions by role](https://help.gladly.com/docs/managing-users-and-roles#roles-and-responsibilities) |
| --- | --- |

SMS/MMS may fail to be delivered due to one of the errors below that appear on the Conversation Timeline.

![Messages indicating A2P 10DLC registration issues and delivery failures for SMS communication.](https://cdn.us.document360.io/7047b671-c4f2-4df0-bb0a-b9b511fd2452/Images/Documentation/a2p-10dlc-error.webp)

## The number used is not A2P 10DLC registered

> *The number used is not A2P 10DLC registered. Please use an alternate form of communication.*

You must send a request to completed the [A2P 10DLC registration](https://help.gladly.com/docs/toll-free-number-verification-and-a2p-10dlc-registration-process#a2p-dlc-registration) for the phone number in question. You cannot use the phone number to send SMS/MMS until the registration is complete. Use another SMSable phone number (if available) or another Channel (e.g., email) to contact the Customer.

## The number used is pending A2P 10DLC registration

> *The number used is pending A2P 10DLC registration. Please use an alternate form of communication.*

Use another Channel (e.g., email) to contact the Customer. The number can be used again once the registration is complete.