Chirpstack Server Not working after 2 downlink messages

Hello all,
I have installed the Chirpstack on Ubuntu 18.04 running on an AWS server. I am able to receive all uplink messages sent after 10 seconds each.
I use MQTT (using Node-Red) to schedule downlinks, but after 2 downlinks, I stop receiving uplink and downlink messages both.
Again once I reset the node, I receive all the uplink messages sent after 10 seconds each and the problem starts again once.

The downlink function is as follows:

var message ={
“confirmed”: true, // whether the payload must be sent as confirmed data down or not
“fPort”: 10, // FPort to use (must be > 0)
“data”: “Qq==” // base64 encoded data (plaintext, will be encrypted by ChirpStack Network Server)
}
msg.payload = message;
return msg;

Please help me solve the issue.

it fully depends on your endnode device, and what you trying to send to it.
ask the endnode manufacturer about that.

Thank you for your reply, I have an Arduino nano and an RN2483 as the end node. The uplinks seems very good but why the error with downlinks?

After two downlinks my end node is still sending successful transmissions in the uplink but it is not received in the gateway tab of the chirpstack or the applications tab, then how can it be an issue of the end node manufacturer. I made the end node and it simply sends 10 as the payload after every 10 seconds in IN865 band.

RN2483 FW 1.0.5 hangs after receiving LinkADRReq+DevStatusReq

He has a similar problem as I face. Thanks for your reply.