RFM95 Downlink Problem

Hi, Iam using RFM95 as lorawan transmitter to the RAK Lorawan Gateway. Uplink data is successfully transmitted, but not with downlink data, apparently it has issue with RX_Timeout that keep appear after successfully transmitted an uplink Data. I tried send downlink data to node but failed due to this Issue.
here the debug result:
Mbed LoRaWANStack initialized

CONFIRMED message retries : 3

set class OK

Adaptive data rate (ADR) - Disable

set datarate OK

Connection - In Progress …

Connection - Successful
[2K[39m[INFO][LMAC]: RTS = 14 bytes, PEND = 0, Port: 6[0m

14 bytes scheduled for transmission
[2K[31m[ERR ][LMACC]: Invalid MAC command (0x0)![0m
[2K[31m[ERR ][LSTK]: RX_ERROR: mcps_indication status = 1[0m

Message Sent to Network Server

Error in reception - Code = 9
[2K[39m[INFO][LMAC]: RTS = 14 bytes, PEND = 0, Port: 6[0m

14 bytes scheduled for transmission
[2K[31m[ERR ][LMACC]: Invalid MAC command (0x0)![0m
[2K[31m[ERR ][LSTK]: RX_ERROR: mcps_indication status = 1[0m

Message Sent to Network Server

Error in reception - Code = 9

Error no 9: RX_ Timeout
mcps_indication status no 1: LORAMAC_EVENT_INFO_STATUS_ERROR

Any solution would be appreciated
Thanks