> For the complete documentation index, see [llms.txt](https://docs.monogoto.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.monogoto.io/advanced-console/sms-in-monogoto-network/sms-que-functionality.md).

# SMS Queue Functionality

In this section you may learn about the SMS retry times, when the SMS failed to be delivered.

Monogoto system has an SMS queue functionality that will attempt to deliver your SMS in case it failed to deliver. Below you can find some information on the SMS failures and the SMS retry attempts when the SMS failed to be deliver.

| SMS failure message in portal                               | Failure message explanation                                                                      | SMS delivery retry times in seconds                                                                                                                                                                                                             |
| ----------------------------------------------------------- | ------------------------------------------------------------------------------------------------ | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| "blocked by a Security Rule"                                | SMS are blocked by Security rules in portal                                                      | SMS retry will not be attempted                                                                                                                                                                                                                 |
| "Sms MT is blocked for Thing"                               | MT SMS are currently blocked in Thing Menu or whole account                                      | SMS retry will not be attempted                                                                                                                                                                                                                 |
| "is blocked by a Thing setting"                             | SMS functionality is blocked in Thing Menu or whole account                                      | SMS retry will not be attempted                                                                                                                                                                                                                 |
| <p>"Absent Subscriber" / <br>"Absent Subscriber for SM"</p> | SIM card is currently not connected to an operator or the device is currently not enabled        | <p>1st attempt - 300s</p><p>2nd attempt - 900s</p><p>3rd attempt - 1800s</p><p>4th attempt - 2700s<br>5th attempt - 3600s</p>                                                                                                                   |
| "Subscriber Busy for MT SM"                                 | SIM card is currently busy and can not receive SMS                                               | <p>1st attempt - 4s</p><p>2nd attempt - 6s</p><p>3rd attempt - 8s</p><p>4th attempt - 10s<br>5th attempt - 30s</p><p>6th attempt - 60s</p><p>7th attempt - 120s</p><p>8th attempt - 240s</p><p>9th attempt - 480s</p><p>10th attempt - 680s</p> |
| "System Failure"                                            | SMS delivery failed due to system or protocol related reasons                                    | <p>1st attempt - 10s</p><p>2nd attempt - 30s</p><p>3rd attempt - 60s</p><p>4th attempt - 120s</p>                                                                                                                                               |
| "SM Delivery Failure"                                       | <p>SMS failed to deliver due to one of the below reasons: </p><p>-Unknown Service Center Address |                                                                                                                                                                                                                                                 |

</p><p>-Service center congestion
</p><p>-Invalid short message entity address</p> | <p>1st attempt - 10s</p><p>2nd attempt - 30s</p><p>3rd attempt - 60s</p><p>4th attempt - 120s</p><p>6th attempt - 300s</p><p>7th attempt - 900s</p><p>8th attempt - 1800s</p><p>9th attempt - 2700s</p><p>10th attempt - 3600s</p>              |
| "UNIDENTIFIED\_SUBSCRIBER"                                  | <p></p><p>SIM card is currently not connected to an operator or the device is currently not enabled</p>                                                                             | <p>1st attempt - 10s</p><p>2nd attempt - 30s</p><p>3rd attempt - 60s</p><p>4th attempt - 120s</p><p>6th attempt - 300s</p><p>7th attempt - 900s</p><p>8th attempt - 1800s</p><p>9th attempt - 2700s</p><p>10th attempt - 3600s</p>              |
| "UNEXPECTED\_DATA\_VALUE"                                   | <p>SMS was rejected by the operator due to <br>decoding error or signaling fault</p>                                                                                                | <p>1st attempt - 10s</p><p>2nd attempt - 30s</p><p>3rd attempt - 60s</p><p>4th attempt - 120s</p><p>6th attempt - 300s</p><p>7th attempt - 900s</p><p>8th attempt - 1800s</p><p>9th attempt - 2700s</p><p>10th attempt - 3600s</p>              |