Error 21408 occurs when you attempt to send an SMS or MMS to a country or region that is not enabled or supported for messaging. These regional controls help prevent messages from being sent to destinations your account is not configured to use and can also help avoid unexpected international messaging charges.

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What Is Error 21408?

Error 21408 means the destination country or region is not currently available for messaging from your account.

This can happen because:

  • The destination region is not enabled for your account.

  • The destination is not supported for SMS or MMS.

  • Regional restrictions prevent delivery to that country.

  • The destination number uses a country prefix associated with a blocked or unsupported region.

Key Benefits of Regional Messaging Controls

Regional messaging restrictions help keep outbound messaging predictable and compliant.

  • Reduced Unexpected Charges: Prevents accidental messaging to unsupported international destinations.

  • Safer Account Configuration: Limits messaging to regions your business is approved to use.

  • Improved Compliance: Helps enforce country-specific messaging restrictions.

  • Clearer Troubleshooting: Makes it easier to identify destination-related delivery failures.

Common Causes of Error 21408

Error 21408 typically appears when the destination country is outside the messaging regions currently available to your account.

Common causes include:

  • The destination region has not been enabled.

  • The contact’s phone number belongs to a country you do not normally message.

  • The destination is subject to platform or regulatory restrictions.

  • The phone number contains an incorrect country code.

  • A workflow or campaign is attempting to send to an international contact unexpectedly.

How to Fix Error 21408

Start by confirming that the destination number and country are correct.

  1. Review the destination phone number.

  2. Confirm the number uses the correct international country code.

  3. Identify the recipient’s country or region.

  4. Confirm that messaging to that destination is supported.

  5. If the region is supported but not enabled for your account, contact support to request assistance.

  6. If the region is restricted or unsupported, use another supported communication channel when appropriate.

Check the Destination Country Code

An incorrect country code can make a valid contact appear to be located in an unsupported region.

Confirm that the phone number is saved in international format:

+[country code][subscriber number]

For example:

+442071234567

If a contact was imported or entered manually, review the number for missing or incorrect country prefixes.

Unsupported or Restricted Regions

Some destinations may be unavailable because of regulatory, carrier, or service restrictions.

For example, traffic to recipients in Iran is not supported. This applies to phone numbers using the +98 country code.

Voice, messaging, and email traffic to recipients in Iran is restricted under the current service policy.

If you are trying to contact a recipient in a restricted region, changing the account settings will not override the restriction.

Check Automated Workflows and Campaigns

If Error 21408 appears during automation, the message may be going to a contact in an unexpected country.

Review:

  • Contact phone number

  • Country code

  • Workflow audience

  • Campaign recipient list

  • Imported contact data

  • Form submissions

  • Custom phone fields

This is especially important when a single campaign includes contacts from multiple countries.

Frequently Asked Questions

Q: What does Error 21408 mean?
It means the destination country or region is not enabled or supported for messaging.

Q: Can I enable the region myself?
In some cases, support may need to enable an eligible region for your account.

Q: What if the country is completely unsupported?
If the destination is restricted or unsupported, messaging cannot be enabled for that route.

Q: Does Error 21408 apply to both SMS and MMS?
Yes. The error can occur for both SMS and MMS traffic.

Q: Can a wrong country code trigger this error?
Yes. If the number is saved with an incorrect international prefix, the system may interpret it as belonging to the wrong region.

Q: Does this affect automated messages too?
Yes. Workflows, campaigns, and other automated sends can fail with Error 21408 if the destination region is unavailable.

Need Help?

If Error 21408 continues, first confirm the destination number, country code, and recipient region.

Verify that:

  • The destination number is formatted correctly.

  • The correct country calling code is included.

  • The recipient is actually located in the country indicated by the number.
  • The destination region is supported for messaging.

  • The destination region is enabled for your account when required.

  • The workflow or campaign is not sending to unintended international recipients.

  • Imported or form-submitted phone numbers have the correct country codes.

  • The destination is not in a restricted region.

  • The number does not use a blocked country prefix such as +98.

If the region should be supported but is not enabled, contact support for assistance. If the region is restricted, the message cannot be delivered through that route.

If the issue continues, collect the sender number, destination number, recipient country, message type, campaign or workflow name if applicable, and a screenshot of Error 21408 before contacting support.