Can't read datas sent wirelessly to a Xbee module with Arduino

Hi, I’m using Arduino to acquire datas from an external high performance ADC through the SPI bus.
I have configured two Digi Xbee S2C modules with the XCTU software. One module is configured as a coordinator and the other is not. They’re both using AT/transparent mode.
Using the serial console embedded in the XCTU sofware the two modules work when both connected to a PC (the modules are installed on their development board and connected via USB).
I can send and receive datas in both directions from both modules.

Now what I want to do with my project is:

  1. Connect one Xbee module (the router or end device) to Arduino to send the datas acquired from the external ADC mentioned before to the module connected to the PC (the coordinator) and print the datas on the serial console (within XCTU or Putty).
    2)At the same time I want my coordinator (the Xbee module connected on my PC) to send simple serial commands to Arduino (‘y’ or ‘n’) to start/stop the acquisition.
    I’ve connected the Xbee module to Arduino using a simple 4 pin setup (GND,VCC,DOUT,DIN).

The first goal is perfectly achieved, all my datas are sent from Arduino to the Xbee module connected to my PC.
The second part doesn’t work.
It seems like the Xbee module connected on Arduino receives the commands that the coordinator is sending but doesn’t forward them through the TX pin on the Arduino’s serial port so Arduino has nothing to read.

I’ve tried to do the same thing using a Bluetooth module with the same 4 pin setup and it works as intended using a smartphone app to both visualize and send datas, so I don’t think it’s a problem with the hardware connections or with the code I’m using (which is fairly simple relatively to part to the part of reading and sending datas on the serial port).

Am I missing something? Should I configure the Xbee modules differently?
Maybe the end devices don’t forward automatically the datas they receive wirelessly on their TX pin?

Thank you for your help!!