Why is the serial communication with this device failing?

I have two serial to USB adapters connected to my computer, each one is connected to a microcontroller. What I want to do is send commands to each microcontroller through UART (I'm using minicom), but only one is succeeding. Both send data to the computer, but only one is capable of receiving it. This is the result after sending a command to one device. This is what happens with the other device. It's not that the connection is wrong, because I switched to Windows and both of them worked. Also, I have to add that the adapter started to fail when I attempted to transmit information to both devices at the same time (as *ttyUSB0* and *ttyUSB1*). It was working fine before that attempt. After that, it doesn't matter if only one is connected, one always works and the other doesn't. It is recognized by the computer as *ttyUSB0* but it never receives the information. As more evidence that it's the software that is wrong and not the hardware: the LED of the failing adapter never turns on when it's supposed to be receiving data. Edit: information about the two adapters and the microcontrollers. **Device CH341** [11208.020500] usb 3-2.3: new full-speed USB device number 23 using xhci_hcd [11208.222337] usb 3-2.3: New USB device found, idVendor=1a86, idProduct=7523, bcdDevice= 2.64 [11208.222345] usb 3-2.3: New USB device strings: Mfr=0, Product=2, SerialNumber=0 [11208.222348] usb 3-2.3: Product: USB Serial [11208.232359] usb 3-2.3: ch341-uart converter now attached to ttyUSB0 **Device FT232** (the one that doesn't receive data) [11208.400547] usb 3-2.1.4: new full-speed USB device number 24 using xhci_hcd [11208.613046] usb 3-2.1.4: New USB device found, idVendor=0403, idProduct=6001, bcdDevice= 6.00 [11208.613056] usb 3-2.1.4: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [11208.613060] usb 3-2.1.4: Product: FT232R USB UART [11208.613062] usb 3-2.1.4: Manufacturer: FTDI [11208.613065] usb 3-2.1.4: SerialNumber: A9EYI2C0 [11208.621661] usb 3-2.1.4: Detected FT232RL [11208.623137] usb 3-2.1.4: FTDI USB Serial Device converter now attached to ttyUSB1 The microcontrollers are both Black Pill boards (STM32F401)