Join accept are shown but nothing happen

Hello Chirpstack community,

I just deployed my new Chirpstack infrastructure but i’m facing a strange issue.

I have several sensors of the same model, they were all connected to a previous network server (not Chirpstack) and i changed it to Chirpstack stack.

Once the migration was done i rebooted all the sensors, some of them were joining the network perfectly : Join request -> Join Accept -> Up (data)

But others are still not connecting. In the Lorawan frame reader i can see :
Join Request -> Join Accept -> Join Request -> Join Accept -> Join Request -> Join Accept -> …

Which means my gateway (Multitech Conduit IP67) is able to see the sensor and is validating the keys but it’s like the sensors are not receiving the join accept…

I’ve seen multiple topics about this kind of issue but i haven’t find any solution, can it be linked to the downlink frequency ? (if yes what should i configure for EU? and why some sensors are working?)

PS: to be more precise some sensors were directly working, one reboot and they connected, but some needed 2,3 or 4 reboot to join, they kept sending join request and they received the joined by chance one time (so maybe the frequency/ADR/SF was good this time?)

Thanks a lot it will be incredible if i can solve this :pleading_face:


Ok, just tried to put a sensor closer to the antenna and it directly connected. What is strange is that the antenna was able to receive the join request before, so it’s not a coverage distance issue (?)

I think that the downlink join accept is not able to be received by the sensor when it’s far so it may be link with the SF/ADR or something… no idea


Downlinks are working for 868100000 frequency but when my sensor is far it’s using 868300000 or 867300000. It seems that only 868100 is able to send downlink that’s why it can connect when it’s close to the antenna but other frequencies are not handling downlinks… how can i configure this ?


Did you find an answer for this ?

Experiencing the same issue.

Don’t be so sure - this video gives very practical information (stop at 6:00 minutes mark).

Same gentleman has other great LoRaWAN-specific videos on antennas:
Basic antenna theory & recommendations for LoRaWAN users
Using $140 antenna analyzer to verify your antenna is good Video makes use of N1201SA
Why need ground-plane for Monopole antennas

The “guy with the Swiss Accent” is also highly recommended (love his dry humor). There are other good videos I’ve stumbled upon.

  • Did you learn something valuable in videos linked above?

0 voters

Anyone have their favorites they’d like to share (useful to practical using of LoRaWAN hardware, not too technical/esoteric please).

P.S. Many years ago I earned a EE and took one antenna theory class that I barely understood and didn’t see any application for in my intended career. Then LoRaWAN was invented…


Hi @fmgst ,
did you find any solution to your problem ?
I am facing the same problem for some of my sensors.

It looks to me that this is a “catch all” error that can mean several different failure modes, each with a different solution. I say this because I’ve encountered that already.

Caveat: problem with below list is that a cause I propose CAN NOT cause a join problem, but it happen to me by sheer coincidence so I think it does. Thus, I welcome more experienced members to critique and dispute entries - it’s really helpful to me, personally.

  • Firmware bugs - updating firmware and, in one case, flashing same version solved issue (??)
  • Hard-cycling sensor by removing batteries; just resetting via OTAA didn’t “take”
  • Purchasing used sensor, with new AppKey correctly programmed, it didn’t want to join until reflashed firmware. This happened to me and also @Chouffi, above.
  • Placing sensors physically too close gateway - that bit me on first week I was experimenting with LG191 & qty 8 RS191 sensors. I wasted easily 20 hours scouring my software configuration, when problem was physical. Solved accidentally by taking sensor with me to the car - it transmitted 100% reliably from my car in the parking lot :slight_smile:

Didn’t happen to me (yet), but these appear to be other causes that manifest same way:

That’s all I know.