These are the response codes you can expect 98% of the time.
- 0: Message sent successfully to the wireless network operator
- 4: Message delivered to handset
- 3: Message buffered with carrier and waiting for a response, the status should change to 0, 4, or ESME_ROK eventually.
- 1070: Invalid phone number
- 1001: Blocked by Wire2Air Gateway. The user has opted out. To enable delivery, have the user rejoin your campaign by texting a keyword to your assigned short code. If the user opted out in error and can't be joined by a keyword, open a ticket with support to remove the block.
Status: 0 The Carrier acknowledgments indicate delivery to the carrier, but do not mean that the destination handset received the message.
Status 4 is a Handset delivery receipt that indicates successful message delivery to the destination handset, but it's important to note that not all carriers support Handset delivery status.
You'll receive status 4 for carriers who offer handset-level delivery status reports. Not all carriers provide handset delivery reports. The USA carriers provide handset delivery reports are:
- AT&T
- Cincinnati Bell Wireless
- Cricket
- T-Mobile
- US Cellular
- Verizon
Rule of thumb: Delivery statuses 0, and 4 can be considered as "Message successfully delivered" and all other statuses are failed.
For the rest of the carriers, you would receive the status "0" which means the carrier has accepted the message successfully.
The lack of a handset acknowledgment does not imply that the message was not delivered to the subscriber, it just means that the carrier hasn't given us any acknowledgment.
Exception
The carrier may reject a message due to many reasons, and most of the time their error codes are ambiguous that's why we can't provide a predefined set of response codes, these codes can change from time to time. There is no universal standard for these error codes, each carrier has its own set of errors.
On our end, we have a logic to retry some of the failed messages via an alternate route.
Since the alternate route doesn't provide reliable delivery reports, so we can't guarantee that message will be delivered. But based on our experience 90% of failed messages can be delivered via alternate route. These are two possible response codes from alternate route:
delivered and undelivered.
Final Word:
For the most part over 98% of messages will be delivered without any issues. There might a failure for a few smaller carriers' numbers, prepaid phones, or if someone doesn't have text messaging enabled on their account.