When a LWM2M client is offline, the LWM2M server does not send downlink requests to the client instead waits until the LWM2M client is online on the transport layer. When the client is online all the stacked up requests are handled sequentially. The queue history lists all the commands issued to the client with the sequence that will be executed when the client is back online.
Once added in the queue, a message will be automatically transmitted again for a second attempt once the device sends its next registration update. In case of failure due to missing confirmation of the delivery from the device, a timeout error will be shown in the Error column. No additional attempts will be performed. Once transmitted, the message will be deleted after 30 days.
Clicking the Queue History button in LWM2M tab will open a window listing the log of all the queries sent to the remote device.
The Error column, the last one from left to right, will display the results of the operation if it ends in a failure on re-transmission.
To stop the commands which are yet to be transmitted, click delete 
corresponding to the command.
