Failed to send downlink messages

Issue: downlink packet from app server [node red] to node failed

Setup: rak 7258 built in lora server with external MQTT Integration

LoRa® Server: built in lora server

Details: i m using heltec wirekess stick with rak 7258 gateway.
using built in lora server of gateway with external MQTT Integration.
i am trying to send some data from node to app server which is node red instance. and trying to turn ON/OFF led of node from node red.
node is configured in ABP mode, Class C.
i am successfully recieving node data in node red however downlink not working.
i am using ESP32Lorawan_master Library.
if i send downlink data from gateway under appliction , node is gatting ON/OFF command. if i send same data from node red, node not responding.
no downlink data received in live device data.

What method is used to send downlink data? When you send the downlink, can you receive it on the server?

i am sending data from node red. sending “31” to turn ON led and “32” to turn OFF.
YES i am receiving this data in system log

1 Like


Great!You have solved your problem?

gateway receiving from app server but gateway not forwarding to node. there is no downlink packet in live device data window.
if i manually send this data from gateway downlink panel, then live device data show downlink packet and node responding accordingly…however this is not happening from node red to end node.


I can see that the server has sent data normally, but the node has not received it. This is very strange. Maybe you can try to test with our node to see if it can receive successfully.

i tested node. and its working good if i send data manually.


But when you send it through MQTT, he will not be able to receive it normally, right?

yes this is the issue…


Can you tell me which mqtt server you use?

Mosquito …


You must ensure that these parameters are correct and the delivery format is correct.

E.g:mosquitto_pub -h -t ‘application/2/device/2222222222222222/tx’ -m ‘{“confirmed”: true,“data”: “SGVsbG8=”,“fPort”: 10}’

Hi Dear.
this is my downlink topic. is that correct…?

Dear QN,

You need recover the setup!

Best regards!

dear i m sorry . i did not understand what you want to say…
kindly explain briefly…

Dear QN,

I want you to change your uplink topic and downlink topic!

uplink topic:application/{{application_ID}}/device/{{device_EUI}}/rx

downlink topic:application/{{application_ID}}/device/{{device_EUI}}/tx

Best regards!

dear i tried several methods of topic. with curly braces uplink topic dosent work. and downlink topic is no hope. with curly braces and without curly braces…there is no output…

Dear QN,

Perhaps you can change the subscribed topic to #

# for subscribing to everything

Best regards!