# SMPP Error Codes

All errors on the SMPP connection received in `submit_sm_resp` are described in the [SMPP Protocol Specification v3.4 Issue 1.2 chapter 5.1.3 command\_status](https://smpp.org/SMPP_v3_4_Issue1_2.pdf#page=112)

## Message state information

A message will always be in one of the following states:

<table><thead><tr><th width="187">Message State</th><th width="75.33333333333331">Value</th><th>Description</th></tr></thead><tbody><tr><td>ENROUTE</td><td>1</td><td>Message is in the process of being sent to the destination</td></tr><tr><td>DELIVERED</td><td>2</td><td>Message has been delivered to destination</td></tr><tr><td>EXPIRED</td><td>3</td><td>Message validity period has expired</td></tr><tr><td>DELETED</td><td>4</td><td>Message has been deleted</td></tr><tr><td>UNDELIVERABLE</td><td>5</td><td>Message is undeliverable</td></tr><tr><td>UNKNOWN</td><td>7</td><td>Message is in invalid state</td></tr></tbody></table>