Messaging requirements vary depending on where your phone number is located and where the recipient is located. Some messaging routes require A2P registration, while others can use completed identity verification instead. Understanding these requirements can help prevent blocked messages and make troubleshooting common messaging errors easier.

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What Are A2P Registration and Identity Verification?


A2P registration verifies businesses that send application-generated SMS or MMS traffic over supported U.S. and Canadian messaging routes. Identity verification confirms the identity of the person or business using the phone number when A2P registration is not required for a particular route.

The requirement applied to a message depends on the sender number, recipient country, and—in some Canadian scenarios—when the phone number was purchased.


Key Benefits of Messaging Verification

Completing the appropriate registration or identity verification helps ensure your messaging traffic meets carrier and routing requirements.

  • Improved Deliverability: Properly verified numbers are less likely to have messages blocked for missing registration.

  • Clearer Compliance: Registration identifies legitimate business messaging traffic.

  • Simpler Troubleshooting: Error codes can help identify which verification requirement is missing.

  • International Flexibility: Some international routes can use identity verification without requiring A2P registration.

  • Reduced Messaging Disruptions: Completing verification before sending helps prevent avoidable delivery failures.


Domestic Messaging Requirements

Messages sent between numbers in the United States, Canada, and Puerto Rico may be subject to A2P registration requirements.

For most domestic messaging routes, the sending number must have an approved A2P registration.

Examples include:

  • U.S. number → U.S. number

  • U.S. number → Canadian number

  • Canadian number → U.S. number

  • Canadian number → Puerto Rico number

If A2P registration is required but missing, the message may fail with:

Error 30034 — Number not A2P compliant. Register the number for A2P messaging.


Canadian Number-to-Canadian Number Messaging

Canadian-to-Canadian messaging has different requirements depending on when the sending phone number was purchased.

Numbers Purchased Before March 26, 2025

Canadian numbers purchased before March 26, 2025 can continue sending Canadian-to-Canadian messages without completing A2P registration under the applicable routing rules.

Numbers Purchased On or After March 26, 2025

Canadian numbers purchased on or after March 26, 2025 can send Canadian-to-Canadian messages when either:

  • A2P registration is complete, or

  • Required identity verification is complete

This exception applies specifically to Canadian-to-Canadian messaging and should not be assumed to apply to other domestic routes.


International Messaging Requirements

Messages sent from U.S. or Canadian phone numbers to many international destinations do not require A2P registration. Instead, the sender must complete identity verification.

For supported international routes:

  • A2P registration is not required solely because the message is international.

  • Identity verification must be completed when A2P registration is not present.

  • Messaging can resume after the required identity verification is approved.

For example:

  • U.S. number → France: Identity verification required

  • Canadian number → Australia: Identity verification required

Error 1002: A2P or Identity Verification Required

Error 1002 indicates that the message was blocked because the sending number does not have the verification required for that messaging route.

The error may appear when:

  • A2P registration is not complete, and
  • Identity verification is also incomplete

Error 1002 — Message blocked. A2P or identity verification required.

If the route supports identity verification instead of A2P registration, complete the verification process before attempting to send again.


How to Complete Identity Verification

Identity verification may be required before international messaging or certain Canadian messaging routes can be used.

If verification was not requested when the phone number was purchased, use the available identity-verification workflow in your account to begin the process.

Complete all requested identity steps and wait until verification is approved before testing messaging again.

Do not repeatedly send blocked messages while verification is still pending.


UK Messaging Restrictions

The United Kingdom has additional routing restrictions that differ from other international destinations.

Messages sent from a U.S. number to a UK number are not supported under the routing described here.

Attempts to use this route may return:

Error 21612 — Message cannot be sent with the current combination of To and/or From parameters.

UK-to-UK messaging is supported separately and is not subject to the same U.S.-to-UK restriction.


Messaging Requirements at a Glance

The correct verification method depends on the sender and recipient combination.

Messaging RouteRequirement
U.S. → U.S.A2P registration
U.S. → CanadaA2P registration
Canada → U.S.A2P registration
Canada → Puerto RicoA2P registration
Canada → Canada, number purchased before March 26, 2025A2P not required under this exception
Canada → Canada, number purchased on/after March 26, 2025A2P registration or identity verification
U.S./Canada → supported international destinationIdentity verification
U.S. → UKNot supported under this route

Common Messaging Errors

Understanding the error code can help identify the next action to take.

Error 30034
The sending number requires A2P registration but is not properly registered.

Error 1002
The messaging route requires either A2P registration or identity verification, and neither requirement has been satisfied.

Error 21612
The sender and recipient number combination is not supported for that messaging route.

Best Practices Before Sending Messages

Checking registration and routing requirements before launching campaigns can help prevent unnecessary delivery failures.

  • Confirm the sender number's country.

  • Confirm the recipient's country.

  • Complete A2P registration for domestic routes where required.

  • Complete identity verification before using eligible international routes.

  • Verify the registration or verification status before sending bulk messages.

  • Test a small number of messages after approval before increasing volume.

  • Review error codes rather than repeatedly retrying blocked messages.

  • Do not assume that one country's exception applies to another messaging route.

Frequently Asked Questions

Q: Does every message from a U.S. or Canadian number require A2P registration?
No. Domestic routes commonly require A2P registration, while supported international routes may require identity verification instead.

Q: What does Error 30034 mean?
It means the sending number is being used on a route that requires A2P registration, but the number is not currently A2P compliant.

Q: What does Error 1002 mean?
It means the message was blocked because the required A2P registration or identity verification has not been completed.

Q: Do Canadian-to-Canadian messages always require A2P registration?
No. Requirements depend on when the sending Canadian phone number was purchased. Newer numbers may use either A2P registration or completed identity verification for Canadian-to-Canadian messaging.

Q: Is A2P registration required when messaging internationally?
For the supported U.S.- or Canada-to-international routes described here, identity verification is required instead of A2P registration.

Q: Can I send SMS from a U.S. number to a UK number?
Not through the route described here. Attempts may fail with Error 21612.

Q: Will messages start working immediately after identity verification is approved?
Messaging should become eligible once the required verification is successfully completed, although normal carrier processing and delivery conditions still apply.


Need Help?

If messages are being blocked after completing A2P registration or identity verification, first review the sender country, recipient country, and verification status.

Verify that:

  • The sending phone number is active.

  • The sender and recipient countries are identified correctly.

  • A2P registration is approved for domestic routes that require it.

  • Identity verification is approved for routes that allow it instead of A2P registration.

  • Canadian-to-Canadian messaging is being evaluated based on the phone number's purchase date.

  • The message is not being sent over an unsupported U.S.-to-UK route.

  • The registration or verification process is fully approved rather than pending.

  • The affected phone number is associated with the correct approved registration.

  • You have reviewed the exact error code returned for the failed message.

  • Enough time has passed for newly approved registration or verification changes to take effect.

If you receive Error 30034, review the A2P registration for the sending number. If you receive Error 1002, confirm that the required A2P registration or identity verification has been completed. If you receive Error 21612, review whether the sender and recipient combination is supported.

If the issue continues, collect the sending number, recipient country, messaging route, A2P status, identity verification status, phone number purchase date when applicable, error code, and screenshots of the failed message before contacting support.