| Code | Description |
|---|---|
| 4121 | Rejected as SPAM |
| 4301 | Malformed message encoding |
| 4302 | Malformed From number |
| 4303 | Malformed To Number |
| 4350 | Malformed message encoding |
| 4401 | Message is looping from carrier back to BW |
| 4403 | Messaging forbidden on From number |
| 4404 | Messaging forbidden on To number |
| 4405 | Unallocated from number |
| 4406 | Unallocated to number |
| 4410 | Could not download media |
| 4411 | Combined size of media too large |
| 4420 | No Route to Destination Carrier |
| 4421 | No Route to Destination Carrier |
| 4431 | Messaging on shortcode forbidden |
| 4432 | Messaging to country forbidden |
| 4433 | Messaging on Toll Free Number Forbidden |
| 4434 | Messaging to Toll Free Number Forbidden |
| 4451 | Invalid User Id |
| 4452 | Invalid Application Id |
| 4470 | Rejected as SPAM (future) |
| 4481 | From Number in black list |
| 4482 | To Number in black list |
| 4492 | Message to emergency number forbidden |
| 4493 | Unauthorized |
| 4700 | Carrier Rejected as Invalid Service Type |
| 4720 | Carrier Rejected as Invalid Destination Address |
| 4740 | Carrier Rejected as Invalid Source Address |
| 4750 | Carrier Rejected Message |
| 4751 | Message too long for carrier |
| 4770 | Carrier Rejected as SPAM |
| 4775 | Carrier Rejected due to user opt out |
| 5100 | Application Error |
| 5101 | Application Error |
| 5111 | Application Error |
| 5112 | Application Error |
| 5143 | Application Error |
| 5144 | Application Error |
| 5146 | Application Error |
| 5201 | Application Error |
| 5211 | Application Error |
| 5220 | Application Error |
| 5231 | Application Error |
| 5500 | General Message Send Failure |
| 5501 | General Message Send Failure |
| 5503 | Service Unavailable |
| 5600 | Carrier Service Unavailable |
| 5610 | Carrier Service Failure |
| 5620 | Carrier Application Error |
| 5630 | Carrier Application Error |
| 5650 | Carrier Service Failure |
| 5999 | Unknown error from downstream |
| XXX | Other error |