ChromeOS Serial Monitor - Doesn't Work with Uno R4 Wifi

[robotsrobots123]

Hello,

The serial monitor doesn't work on my Chromebook when using the Web Editor.

Hardware: Uno Rev 4 Wifi
ChromeOS: 126.0.6478.222 (Official Build) (64-bit)
Uno Rev 4 Wifi FW 0.4.1

Current Setup:

1. I can detect the device and upload code to the device.
2. The device is running the code - see sample below. The builtin LED is on and the Tx LED transmits once a second.
3. This works just find on another Windows Laptop.
4. When I click on the serial monitor, "Connecting..." shows up, and then goes away.

In the upper corner of the serial monitor, I see:
Arduino UNO R4 WiFi
Port: 0x2341/0x1002

CODE

void setup() {
  Serial.begin(9600);
  while (!Serial);
  Serial.println("Setup");
  pinMode(LED_BUILTIN, OUTPUT);
  digitalWrite(LED_BUILTIN, HIGH);  // Turn on LED, so I know setup() completed
}

void loop() {
  Serial.println("Hello");
  delay(1000);
}

I'm a controls engineer by trade and happy to responsively dig deep into suggestions.

I tried changing the baud rate, rebooting the device, reloading the webpage, etc. Hope someone can help!

[robotsrobots123]

This is an interesting one, I have a second Chromebook and this one also connects, downloads, and the serial monitor does work just fine.

They're both requesting and getting permission to serial device "UNO WiFi R4 CMSIS-DAP (ttyACM0)"

Still eager to troubleshoot this - I’m able to debug Chrome via logging and events if needed.