Hi. What code is in your Arduino board? To communicated with RAK811 module you have to use the Arduino like USB to Serial convertor. It is better to use one for this 
Do you have one?
Hello velev thanks for you answer.
I use a the examples provied by rak in this github
I upload the Join network abp sketch.
however I tried to discconect the microcontroler in the board and only connect the tx and rx trasmition but still not working
Hm…strange. Let me check this and will reach you after day or two.
hello！
In the last post, I saw your reply. Did you burn the firmware and BootLoader correctly? 
Hello eveybody! I solved the problem,
for some reason tx of the RAK811 has to go to the TX of my arduino and RX of the RAK811 to the RX of my arduino I suspect that is my convert pin of the RAK811 that is the same of the Xbee module.
Thanks for all.
Hey dude! I am looking for the link that you just shared two years ago, about the code that you used to “combine” Arduino Uno and RAK 811. I couldnot find it
Yo dude, why you asking the same question twice when you’ve brothers waiting to give you the infos on the other thread where you asked the question? You diss’ing us?