DLR: Delivery Reports Status Explained

Below you will find a detailed explanation of the delivery reports status codes.

Message Status
Message unknown The message ID is incorrect or reporting is delayed.
Message queued The message could not be delivered and has been queued for attempted redelivery.
Delivered to gateway Delivery to the upstream gateway or network (delivered to the recipient).
Delivered to mobile Confirmation of receipt on the handset of the recipient.
Error with message There was an error with the message, probably caused by the content of the message itself.
User canceled message delivery The message was terminated by an internal mechanism.
Error delivering message An error occurred delivering the message to the handset.
OK Message received by gateway.
Routing error The routing gateway or network has had an error routing the message.
Message expired Message has expired at the network due to the handset being off, or out of reach.
Message queued for later delivery Message has been queued at the gateway for delivery at a later time (delayed delivery).
Out of credit The message cannot be delivered due to a lack of funds in your account.