Hello David,
I believe the MQTT return values are standard mqtt return values. In the programming reference guide we have the following.
3.53.5 STATUS
Syntax
MQTT "status"
Description
This command allows the retrieval of the current MQTT client status.
Possible values are:
3 The MQTT client is trying to connect.
4 The MQTT client is disconnected.
5 The MQTT client is connected.
Connection process can last a little (depending on the broker, Internet connection...). If errors
occur, they will appear during this connection attempt stage. If it is the first time the setup is
being configured, check the event log or real time log of the device for more information.