Menu

Expand
Rate this page:

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.
Rate this page:

Thank you for your feedback!

We are always striving to improve our documentation quality, and your feedback is valuable to us. How could this documentation serve you better?

Sending your feedback...
🎉 Thank you for your feedback!
Something went wrong. Please try again.

Thanks for your feedback!

Refer us and get $10 in 3 simple steps!

Step 1

Get link

Get a free personal referral link here

Step 2

Give $10

Your user signs up and upgrade using link

Step 3

Get $10

1,250 free SMSes
OR 1,000 free voice mins
OR 12,000 chats
OR more