Quoting from Microchip documentation (found in the demo software section on the RN2483 page):
1] Because of a bug which was present in the RN2483 (v 0.9.5) boot loader. The attempt to update the RN Module code may not succeed on every attempt. RN2483 (V 1.0.0) or RN2903 (V 0.9.5) factory programmed, do not have this issue and will have no issues in the process.
2] If the 1st boot load did not work, the original RN2483 v 0.9.5 code would have been erased,; leaving only the boot loader on the device. Again in the LoRa Development Utility, above the device list, select the checkbox for ?Bootloader Mode?
3] This will allow all available COM ports to be populated on the device list. Select the COM port which was enumerated for the LoRa Mote.
4] Only the DFU tab will be available. Follow steps 5-7 from Update the LoRa RN Module Code until the RN Module is successfully updated.
So you might want to try a couple of times to try revive the device.