Seeeduino Xiao Zephyr Problem

[Lemonochrme]

Hi !
I'm currently trying to run Zephyr on Seeeduino Xiao (SAMD21) with the help of the PlatformIO IDE but I'm facing an issue.
I've created a new project running on Zephyr framework and built this bit of code :

#include <zephyr.h>
#include <stdio.h>

void main(void)
{
    while(1)
    {
        printk("Hello World :)");
    }
}

The building process seems to work properly as well as the uploading to the board.
But once the file is on the board the Xiao isn't recognise anymore (COMx dont show up), and the blue TX LED doesnt blink at all.
I first tought it was a bootloader problem and tried a new one but it doesnt seems to work.

Thank's :)

platformio.ini configuration :
[env:seeed_xiao] platform = atmelsam board = seeed_xiao framework = zephyr