SMS in Close may not deliver for a number of different reasons. Most commonly this would be when you are trying to send an SMS to a number that is not SMS-enabled (such as a landline), or if your content was marked as spam by the receiving phone carrier.
You will notice an error on the SMS activity if our provider Twilio is letting us know that the message was undelivered. By hovering your cursor over the error message, you will see the reason why it was undelivered.
Below are the most common error messages you will see with your undelivered SMS messages:
- Error 30005 "Message Delivery - Unknown destination handset": The destination carrier is reporting the To number is unknown, or no longer in service.
- Error 30003 "Message Delivery - Unreachable destination handset": The destination carrier is reporting the 'To' number is unreachable - the device is likely powered down, out of the service area, or may not accept your messages.
- Error 30007 "Message Delivery - Carrier Violation": The destination carrier is filtering out your messages for delivery. The content of your message was flagged as going against carrier guidelines.
- Error 30008 "Message Delivery - Unknown error": The destination carrier has returned a generic error message.
- Error 30004 "Message Delivery - Message blocked": Your message has been blocked from reaching the destination.
- Error 30006 "Message Delivery - Landline or unreachable carrier": The destination is a landline phone, or the destination carrier can't be reached.
For a more detailed breakdown of the specific error message you are seeing, as well as some tips to troubleshoot you can head over to Twilio's SMS troubleshooting guide here - https://support.twilio.com/hc/en-us/articles/223181868-Troubleshooting-Undelivered-Twilio-SMS-Messages
See SMS Filtering for more details on how to avoid hitting Error 30007 "Message Delivery - Carrier Violation": The destination carrier is filtering out your messages for delivery. The content of your message was flagged as going against carrier guidelines.