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Error 21212

ERROR - 21212

Invalid From Number (caller ID)

You attempted to initiate an outbound phone call or message, but the 'From' parameter you supplied was not a valid phone number or alphanumeric sender ID.

Twilio accepts phone numbers in E.164 format (i.e. "+1 format"), 10-digit US and Canadian numbers with any combination of non-digit separators, or Alphanumeric Sender IDs (SMS only) with up to 11 alphanumeric characters [a-zA-Z0-9].

The number must not be on the do-not-originate (DNO) list, and Alpha Sender IDs may not be generic.

Possible Causes

  • You have supplied a phone number that was not in E.164 format
  • Your From phone number is on the do-not-originate (DNO) list
  • Your alphanumeric sender ID is blocked or too generic

Possible Solutions

  • Ensure your number is formatted in E.164 format
  • Ensure that your From number is assigned and not on the do-not-originate (DNO) list.
  • Ensure you are not using a Messaging alphanumeric sender ID that is too generic (for example, "SMS" or "INFO").
  • If you are getting this error when using a non-generic alphanumeric sender ID, please submit a support ticket for further assistance.
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