time=“2018-12-18T11:51:12+08:00” level=error msg=“schedule next device-queue item error” dev_eui=66ce6f56b1be8828 error=“uplink gateway-history is empty”
“uplink gateway-history is empty” error occurs when the server has no path stored, to send the downlink data.
You should power OFF the device, and POWER it UP AGAIN to save new path to send downlink.
If that doesn’t work, try re-activating the device.
power off the gateway or device ?
As the new uplink message will be sent from device to server via gateway, and this uplink path will be stored at the server end for further downlink messages!