SMS Delivery Issues

SMS delivery failures have specific causes in the U.S. market related to A2P registration and carrier filtering.

Issue: SMS not sending at all

Most common cause: A2P 10DLC registration is not complete or not approved. Settings → SMS → Registration Status. If status is "Pending" or "Rejected," SMS cannot send.

• Pending: Registration is in review. Average approval time: 1–5 business days. No action needed.
• Rejected: Your brand or campaign registration was rejected. Review the rejection reason. Common causes: incomplete brand information, mismatched EIN, or campaign description doesn't match actual use case. Resubmit with corrections.

Issue: SMS sending but not delivering

Carrier filtering blocks messages that look like spam. Check:

• Is the message body over 160 characters? (Creates multi-segment SMS — some carriers filter these more aggressively)
• Does the message contain URL shorteners? (Heavy spam signal — use full URLs)
• Does it contain excessive capitalization, $ signs, or promotional language?

Issue: STOP responses not processing

STOP responses should automatically add the sender to the global unsubscribe list and halt all future SMS. If this isn't happening: Settings → SMS → Opt-Out Keywords. Verify STOP, CANCEL, QUIT, UNSUBSCRIBE are all listed. If the keyword is misspelled in the reply (e.g., "Stp"), it won't trigger automatically — manually add the contact to suppression.