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A2P 10DLC Number Registration Best Practices

While Twilio has designed the A2P registration process to seamlessly register your numbers when associated with an approved Campaign, in some rare instances, failures can occur due to status discrepancies between the multiple parties involved in the ecosystem.  We’re collectively working to complete all A2P registrations quickly and accurately. 

Users of multiple phone numbers should note that antiquated phone number practices to improve deliverability, such as using multiple numbers to increase throughput or rotating them between their customers or use cases, undermine the deliverability benefits of A2P 10DLC and can lead to processing delays and errors. We recommend the following best practices to prevent them.  

Best Practices

• Sender reputation is built by maintaining strong phone number hygiene, consistently using the same number with the registered use case. Avoid reallocating or migrating phone numbers across different users, use cases, accounts, etc.

• Refrain from removing/re-adding numbers from your registered Campaign/Messaging Service or moving numbers between accounts. Each registration/deregistration change requires an independent provisioning process involving downtime while your numbers complete the Number Registration process across the US messaging ecosystem.

• If using Ported or Hosted numbers, make sure your numbers are fully provisioned (e.g.  the Hosted/Ported order is complete) before adding them to your Campaign/Messaging Service. 

What do you need to know?

As part of every A2P registration, Twilio completes various number configurations with US A2P ecosystem partners through a backend process called “Number Registration”. It is triggered when you add a number to a Messaging Service that is associated with an approved US A2P Campaign. Customers will receive a 30035 error when Number Registration is still in progress (e.g. the number status is “Pending Registration” or “Pending Deregistration” when numbers are removed from a Messaging Service). Number Registration often completes within minutes, but under certain circumstances, registration time can fluctuate depending on the volume of registration requests. Twilio is unable to provide processing time guarantees as these are handled by our ecosystem partners. Customers should plan for the possibility of extended Number Registration processing time (up to 24 hours).

PLEASE NOTE: Number Registrations are cumulative and each registration action adds more time to the approval process. Every time a number is removed from a Messaging Service and added to another, a new deregistration and registration request must be processed. Hence, the best practice is to avoid the frequent or routine removal and addition of 10DLC phone numbers.   

Example: Below we’ve outlined the outcome when moving a number between 3 Campaigns (from Campaign A, to Campaign B, and then to Campaign C). Your number will go through two full Number Registration cycles, and its status will change in the order below; each “Pending Deregistration / Pending Registration” step may take up to 24 hours to complete:

Number Status What happens to messages Additional Notes
Registered (to Campaign A) Allowed  
Pending Deregistration (from Campaign A) Blocked with 30035 This step may take up to 24 hours
Unregistered Blocked with 30034  
Pending Registration (to Campaign B) Allowed* *This is a temporary exception; once the exception is lifted, this step may take up to 24 hours during which messages will be blocked with 30035.
Registered (to Campaign B) Allowed  
Pending Deregistration (from Campaign B) Blocked with 30035 This step may take up to 24 hours
Unregistered Blocked with 30034  
Pending Registration (to Campaign C) Allowed* *This is a temporary exception; once the exception is lifted, this step may take up to 24 hours during which messages will be blocked with 30035.
Registered (to Campaign C) Allowed  

In addition, the following actions will trigger number de-registrations automatically and will result in 30035 errors. Please refrain from taking these actions to avoid downtime on your numbers:

  1. Deleting a Messaging Service
  2. Deleting a Campaign that is associated with the Messaging Service
  3. Deleting an account
  4. Releasing numbers from an account
  5. Moving numbers from one account to another

To check the status of your numbers at any given time, see How do I check that I have completed US A2P 10DLC registration.

For more information on how to associate numbers with your Campaign, see How can I associate Twilio numbers with my A2P Campaign.

FAQ

What is Number Registration?

Number Registration refers to a backend process that Twilio goes through to complete the various number configurations for your US A2P DLC Registrations with ecosystem partners. This process is triggered when a customer adds or removes a number to a Messaging Service that is associated with an approved US A2P Campaign. Neither Twilio nor customers can accelerate this process for any one registration. Customers will receive a 30035 error while the Number Registration is still in progress. Do not remove/re-add numbers from your registered Campaign/Messaging Service in response to a 30035 error. Such registration/deregistration changes will result in further delays by starting the Number Registration process over.

How can I check the registration status of my numbers?

To check the status of your numbers at any given time, you can use the Number Registration CSV report as described in How do I check that I have completed US A2P 10DLC registration.

Customers can also set up subscriptions to events which will notify them when a Phone Number's status has changed. This setup and subscription is handled through Twilio's Event Streams product.

How long does Number Registration take to complete?

While number registration often completes within minutes, it can also take up to 24 hours for the number registration to complete. The time for the process to complete fluctuates, and is dependent on the amount of number registration or deregistration requests received. The Number Registration process is dependent on ecosystem technical limitations. Twilio is unable to provide guarantees or estimates on how long this process will take. 

My number has been Pending Registration for multiple days, what should I do?

Number registration can take up to 24 hours to complete. If you have a number pending Number Registration, the best thing to do is wait for it to complete. If your number has been pending registration for more than 24 hours, please contact Twilio Support. Please avoid removing/re-adding numbers to your Messaging Service as these actions are cumulative and will only add more time to the approval process. 

What if my number has been Pending Deregistration for multiple days, what should I do?

Number Deregistration, goes through the same process with each of the ecosystem partners to deregister and requires similar processing time. While number deregistration often completes within minutes, it can also take up to 24 hours to complete. If you have a number “Pending Deregistration”, the best thing to do is wait for ecosystem partner configurations to complete.  If your number has been pending deregistration for more than 24 hours, please contact Twilio Support. Please avoid removing/re-adding numbers to your Messaging Service as these actions are cumulative and will only add more time to the approval process. 

Why am I getting 21703 Errors on a registered Campaign?

If you’re experiencing 21703 errors, this typically means there’s no number available for selection in a Messaging Service as described in: https://www.twilio.com/docs/api/errors/21703

However, while Twilio is temporarily allowing messaging from numbers “Pending Registration” to go through, A2P campaign submissions originally attached to a Message Service with no numbers assigned to it will disable the exception to any number added to that Message Service thereafter. In this case, numbers in “Pending Registration” state and Messaging Service Sender selection on new Messaging Services will not be able to select this number until Number Registration is completed.  If you’re already experiencing 21703 errors, to continue sending messages using a number in the “Pending Registration” state, you should include the number in the "From" parameter of your API request instead of using the Messaging Service SID. 

Any numbers in the Messaging Service that are added PRIOR to campaign registration will not be blocked with a 21703 error while we still have the temporary exception for “Pending Registration” numbers. If you wish to benefit from this exception, add your numbers to your Messaging Service BEFORE registering your Campaign. Once the exception is lifted, customers can expect 30035 errors until the Number Registration process is complete.

Why am I getting 30035 Errors on a registered Campaign?

A 30035 error typically means that the campaign is approved but the 10DLC number is still completing Number Registration (e.g. phone number status “Pending Registration” or “Pending Deregistration”) by our ecosystem partners. 

However, while Twilio is temporarily allowing messaging from numbers “Pending Registration”, this error is likely associated to the removal of a number from a Messaging Service (e.g. “Pending Deregistration”).

While Number Registration often completes within minutes, it can take up to 24 hours to complete. If you have a number pending deregistration, the best thing to do is wait for ecosystem partners to complete the Number Registration process.  If your number has been pending Number Registration for more than 24 hours, please contact Twilio Support.

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