Lost payload on ttn Stack V3

Hi all,
I’m confronted with the problem as Payload is lost between Gateway-Application and NodeRed . No clue why

Gateway… payload present

Recieive Uplink Message
“data”: {
@type”: “type.googleapis.com/ttn.lorawan.v3.UplinkMessage”,
“raw_payload”: “AGTwAdB+1bNwbrJ2eAQpOAA5vUW2y+0=”,
“payload”: {

Application… payload present

receive join-request
“data”: {
@type”: “type.googleapis.com/ttn.lorawan.v3.UplinkMessage”,
“raw_payload”: “AGTwAdB+1bNwbrJ2eAQpOADL4zjwe6A=”,

“forward join accept to application”
!! missing forward data !!

“forward-join accept to application” is making the way to node-red but payload data is lost
something like “forward uplink data message” is missing

Neither a join nor a join accept contains any application data.

You node may not be receiving the join accept and using it; until it does, it can’t send any application data

Node … my end device? …
there should be a second uplink message only with data ? even the payload is already present in the first uplink message included ?

In the Application I can see … “Receive join-accept message”
“name”: “as.up.join.receive”,
“time”: “2021-03-16T21:20:38.955162618Z”,

It doesn’t mean as the join is OK? I think I would need a deeper debug of my transmission or only understanding it better

This is a join packet like @cslorabox told you. Join packets do not contain application data. If you want to know what is in a packet, go to https://lorawan-packet-decoder-0ta6puiniaut.runkit.sh/ and paste the raw payload.

1 Like

That’s one part of the infrastructure telling the other that a join-accept message has been created and will be sent down to the node (end device). No server side log can actually “see” if the node received the join accept.

Before you can get to the point of moving any application data, a gateway has to actually transmit that join accept, and the node has to receive it, decode it, and start using the result. Often the latter fails due to timing issues in the node or mixups about the radio settings applicable to TTN in a given region.

If the next thing the node does is transmit another join request rather than transmit an application data packet, then you know that the join request / join accept process has failed. Until it succeeds, you won’t get any application data.

Also worth noting that some node stacks (for example LMiC) may try to join when the application part of the firmware asks them to send data - if they are not joined, they cannot send data, so they send a join request instead, without any application data as that’s not yet possible until they receive and process a join accept.


I think I face exactly this problem join request after join request without sending any data…
Using mcci-catena/MCCI LoRaWAN LMIC library@^3.3.0
and the second problem is as I don’t know if I have a SX127x or a SX1262 LoRa module on my T-Beam module … don’t know how to find out. There is nothing written on the chip.

Is seems as there is no way “at the moment” to make a SX1262 work …

… does someone have a working example for the ESP32 and SX12xx ? to learn how to communicate with ttn.

If there is no SX1262 mentioned on the label then apparently you do not have a SX1262 version.

There is but you would have to use a different library than LMIC (and there is little experience on the forum with SX1262 in combination with Arduino).

What about searching the forum yourself first?

Have a look at: Big ESP32 + SX127x topic part 3

Start reading at the top. There you will find useful information, including a suggestion for which examples to start with.

If you have a T-Beam v1.x then don’t forget that you will have to configure the power management chip first (at the beginning of setup()), the code for that can be found in the T-Beam topic.

1 Like

This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.