Morning everyone,

I’m currently encountering an issue while using the AT+JOIN command. I’ve noticed that there are some topics discussing similar errors, but none of the solutions have helped me so far. I’m using Chirpstack to host my application and have properly configured the various LoRa parameters. Specifically, I’m operating on the 433MHz frequency and using a 433MHz gateway (NUCLEO-F746ZG + LRWAN_GS_LF1).

Here are my configuration settings:

  • AT+NJM=1 (LoRaWAN)
  • AT+DEVEUI = ac1f09fffe0983B0
  • AT+APPEUI = 00000000000000 (also tried with APPEUI=DEVEUI)
  • AT+APPKEY = 7B077F0DE5415D6CA5C07A187F6EXXXX
  • AT+DR = 4 (SF8)
  • AT+CLASS = 0 (EU433)

When I try to run AT+JOIN, I get the error EVT:JOIN_FAILED_RX_TIMEOUT. Here is the data for the connection attempt from the gateway’s serial port.

LRX: 000000000000000000B08309FEFF091FACDB52FE6EF56B
JUL: {“rxpk”:[{“tmst”:1684181764,“chan”:0,“rfch”:0,“freq”:433.175000,“stat”:1,“modu”:“LORA”,“datr”:“SF8BW125”,“codr”:“4/5”,“lsnr”:11.5,“rssi”:3,“size”:23,“data”:“AAAAAAAAAAAAsIMJ/v8JH6zbUv5u9Ws=”}]}

Perhaps someone might have an idea about the problem ?

Have a good day,

Hi @Aquatwix ,

I have no 433Mhz gateway to test this (let’s wait for @beegee if he has one).

My only idea is only related to my experience with RAK3172 (8xx - 9xx band). There are few times that the module wont join with set of AT commands. But after erasing the flash via STM32CubeProgrammer then upload the latest .hex, it goes back again. I cant recall it but likely related to updating RUI3 firmware very old versions to new one.

Erasing the flash gives a fresh start to the module.

I have a 433MHz gateway, but I have no 433MHz RAK3172 and with RUI3 it is impossible to setup a 8xx/9xxMHz module to 433MHz.

Not sure which RSSI I see in the logs (gateway or node), but the levels are very strange. Never saw RSSI of -5 to -7 or even positive RSSI before. What antennas are you using and how far is the node from the gateway?
What TX power are you using?


AT+CLASS = 0 (EU433)`

Is not setting EU433, it is setting the node class to Class A. I guess you mean



Thank you for your reply. I was using a 433MHz gateway and a 433MHz antenna waiting for my order. I received my 868MHz antenna. However, when I try to configure the EU868 mode using AT+BAND=4, I get an error: AT_UNSUPPORTED_BAND.

Is there a solution to this problem?

There are two hardware versions of the RAK3172

RAK3172 ==> 8xx & 9xx MHz version, only upper frequency LoRaWAN regions are supported. You cannot select EU433 or CN470 regions with that version.

RAK3172(L) ==> 433 or 470 MHz version, only lower frequency LoRaWAN regions are supported. You can check the label of the device. If there is (somewhere) a small (L) printed it is the version for EU433.

You can check the version of the module as well with pin 27 of the module:

The frequency version is fixed with a GPIO inside the module and cannot be changed. The RF path matching of the two versions is different.

Hi @beegee,

Thank you for your response !

After reviewing the module I’ve been using, I’ve realized it’s an (L) module, which isn’t suitable for my requirements. I’ll need to acquire another module that operates on the 868MHz frequency. In the meantime, I’ll attempt to configure the 433MHz gateway. Regarding the initial issue, it seems the gateway might not be connected to the local network, preventing it from initiating the join procedure.

I won’t hesitate to create another topic if I encounter any further issues. I truly appreciate your help !


Sorry, we cannot support your gateways questions as the NUCLEO-F746ZG + LRWAN_GS_LF1 is not our product.

I don’t know anything about that gateway, but I can tell you for our RAK gateways, you need different hardware for EU433 and EU868. None of our gateways does support both.