21610: Attempt to send to unsubscribed recipient

Publisher

Twilio

URL

https://www.twilio.com/docs/api/errors/21610

Published

2026-03-11

Updated

unknown

Accessed

2026-10-02

HTTP status

200

License

Twilio website terms; proprietary; no-redistribution; short excerpts and locators only

Source notes citing this source

• Twilio error 21610 means the recipient has opted out of messages from that Twilio number, Channels sender or Messaging Service. in context
• A recipient blocked under 21610 regains delivery by texting START or another opt-in keyword to the sender; the sending business cannot clear it on the recipient's behalf per the documented process. in context

Cite this source record

APA

WarmTransfer. (2026, March 11). 21610: Attempt to send to unsubscribed recipient. WarmTransfer. https://warmtransfer.net/knowledge/sources/twilio-err-21610-unsubscribed-recipient

BibTeX

@misc{warmtransfer-twilio-err-21610-unsubscribed-recipient,
  title  = {21610: Attempt to send to unsubscribed recipient},
  author = {{WarmTransfer}},
  year   = {2026},
  url    = {https://warmtransfer.net/knowledge/sources/twilio-err-21610-unsubscribed-recipient},
  note   = {Twilio, accessed 2026-10-02}
}