| -1 | (Sent to Network) Message has been sent to the handsets network and is awaiting delivery. |
| 0 | Message has been sucessfully delivered. |
| 1 | Indicates that the targeted mobile subscriber is not valid, as there is no record of it in operator's HLR database; it was either never active or it was permanently de-activated after some time. The delivery toward such numbers is not possible, and the message will receive immediate “undelivered” status. |
| 5 | Indicates that the HLR (or VLR) has no IMSI record for the targeted mobile subscriber at the time of the submission. |
| 6 | This error is returned when a targeted subscriber is in ‘IMSI detach’ state, due to handset being turned off or in low signalling area. |
| 11 | Indicates that the recipient (mobile subscriber) has no SM (Short Message) subscription. |
| 12 | ILLEGAL_EQUIPMENT is one of the rare operator infrastructure related errors that is generic in its description. Basically, this error means that there was an issue concerning the mobile device that was receiving the SMS message, or an issue with the local station the mobile device is connected to. |
| 13 | This error is usually returned when a mobile subscriber has a temporary imposed operator service barring. For example, the subscriber may be restricted to receive SMS, due to unpaid bill. |
| 27 | This error is returned when a targeted subscriber is in ‘IMSI detach’ state, due to handset being turned off or in low signalling area. |
| 34 | Message rejected due to network or protocol failure. This is also a generic error that represents an internal network issue. |
| 256 | The subscriber's message inbox is full; when the inbox memory has been exceeded, further deliver attempts are not possible, not until additional space for storing the same is obtained by deleting old messages. |
| 1153 | Network related error, in most cases indicates that a prefix is missing on operator's platform. |
| 4100 | The message has beendue to the content has been marked as suspicious. |