Downlink transmission failed with Unknown_Error

TTN Network and Services
1

Hello,

Can someone help me understand the problem here or where to look?

I have a device/application sending location information to my local gateway, which mostly works by the looks of things.

The only problem is that I noticed an error message that I am unsure what it tells me.

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I did see there is a similar question to what I am asking in the forum, but it seemed to be unresolved -

What I take away from the message is that at
20:40:02 - A message is received from the Lora device.
20:40:03 - A transmission is sent to the device, scheduling a downlink (is this normal class A behaviour?)
20:40:02 Transmit downlink (this fails with an unknown error)

That is the part I don’t understand - how does my application know that the downlink has failed?
I don’t think that I am requesting a download to the device.

Any suggestions will be appreciated.

Regards
Michael

2

If you would take a minute to check the forum you would find several messages concerning RX1 5 second transmissions, the latest less then two days old…

Short answer, perfectly normal and if there would not be a transmission error your device should get the message only once.

Without additional information (click on the message for json with details, don’t post it as screen shot, copy and past the text and format with the tools at top of the message entry box) it is hard to determine why the downlink fails.

3

Thanks, Jac, for taking the time to help me.

I have got a workaround for the problem,

I am using a SenseCap M2 Modem/Gateway, but I really wanted to use AU915 SFB2, as used by TTN/TTI.

Then, I have a tracker from Seeed Studio, a T1000B.

Since I was having problems, I tried a different approach and set the TTI Gateway as:
Asia 923-925 MHz - (Used by TTN Australia secondary channels)

I Set up the SenseCap Gateway to be:
Region Asia: 923MHz
frequency Plan: AS 923-925MHz

I set up the Device. T1000B from SensCap/Seeed
AS923-2-TTN

This all seems to work well, and I can see Location information on TTN MAPPER, although I could see information using the AU915 plan, too; there are no errors in the application Logging this time.

I am starting to think the problem might be the T1000 tracker device.

What do you think? If I set up the gateway, the modem and the application to use AU915 FSB2, should I not expect the IoT device (T1000B) to have an AU915 and an AU915 FSB2 setting option? Or is the “Downlink transmission failed with Unknown_Error” unlikely to be the reason, seeing that I can read uplink data without problems?

I want to use the correct TTN/TTI Plan on the gateway, which I think is AU915 FSB2 for New Zealand, So I will try to set it up as AU915 again tomorrow. Thank you. I will read about RX1 5-second transmissions and see if that fixes the problem.

Thanks once again for your time, If I have a question, do I just add it here?

4

Configuring your gateway for AU915 (make sure the global_conf.json has the right frequencies and frequency range) and the TTN console set to AU915 should work.

The SenseCAP should support AU915 as well, so give it another try and let us know what happens.

If you have additional questions or information, please continue in this topic so we can easily track progress.