Arduino IoT Cloud and serial port

My setup

  • Arduino MKR WiFi 1010
  • Firefox 94.0.1 (64-bit)
  • ArduinoCreateAgent 1.2.4-056c22e
  • Mac OS 11.6 (Big Sur)
  • Arduino IDE 2.0.0-beta.11

The problem
The Arduino IoT Cloud does not recognise the board on the serial port.
It did recognise it when I set up the project (same setup, just a day ago), but now it does not and it just shows serial port unavailable.

The Arduino IDE is also running, and it is blocking the serial port.

I quit the Arduino IDE, came back to the Arduino IoT Cloud and it was the same, the board was not recognised. Although, going to the Full Editor, it was recognised there. From the full editor, I went back to the IoT Cloud (using the Go to IoT Cloud button), but it was still not working.

Steps I followed then:

  1. Quit the Arduino Create Agent
  2. Quit the browser
  3. Unplug the board
  4. Re-launch the browser
  5. Re-launch the Arduino Create Agent
  6. Replug the board
  7. Go to and check if it’s working

At that point, the board was recognised and I can see messages on the Serial Monitor tab.

The problem is solved, but perhaps there are things that can be done to alleviate it when it happens.

Has this issue happened to other people in this forum? I found an issue from 2017 ([Solved] Serial Port Unavailable…), but the context was different.

1 Like

I have same issue with M5Stack Atom lite and Atom Matrix.
I check issue which Serial1 and Serial2 are not working by serial monitor. but Serial which not numbering is working.

My setup

  • M5Stack Atom lite and Atom Matrix (ESP32-pico)
  • ArduinoCreateAgent 1.2.5-a477c19
  • Google chrome 97.0.4692.71(Official Build) (x86_64)
  • Mac OS Big Sur 11.6.2
  • Arduino editor (Webeditor)
  • Arduino IDE 1.8.13 (Used for Serial monitor)

It seem network function is inhibitioning to use Serial1 and Serial2.

Excerpts from ino file.
It works by excluding the Arduino IoT Cloud function.

void setup() {

  M5.begin(true, false, true);
  Serial1.begin(9600, SERIAL_8N1, 19, 22);

  // Arduino IoT Cloud

void loop() {
  Task1(); // using Serial, Serial1 and Serial2

Does anyone have an ideas?

1 Like

Looks like you have issues with the Wifi Connection, please double-check the password you've entered, and if your wifi router is near enough

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