Text Message Status Values
There are several possible status values for text messages that have been sent. Keep in mind that an SMS message may be relayed through several carriers before reaching its final destination and not all carriers provide delivery receipts.
Sending - the message is being transferred to the nearest upstream carrier
Sent - the nearest upstream carrier accepted the message
Delivered - eAdventist received confirmation of message delivery from the upstream carrier, and, where available, the destination phone
Undelivered - eAdventist received a delivery receipt indicating the message was not delivered. This can happen for many reasons including content filtering, destination phone unavailable.
Failed - The message could not be sent. Possible reasons include unknown number, phone is a landline, recipient has unsubscribed (replied STOP), destination phone is turned off, blocked by carrier spam filter,