450A is a SMS 365, enterprise service status code, which indicates that the mobile terminating (MT) message has been correctly delivered.
Reason for a 450A response
The reason why the 450A status code is returned, and the action which should be taken, is described below:
The MT message sent from HUB Account has been correctly delivered.
Where handset acknowledgement has been requested the 450A indicates, that the message reached the handset and returned a delivery notification.
Where a 450A response has been returned, there are no actions required.
This is a confirmation of message delivery.