[Solved] Monitor: "serial port temporarily busy"

I am using the web editor and an Arduino Uno clone by a Chinese company named Geekcreit. My sketch, which operates a servo motor, runs as expected, but I would also like to see messages written to the serial line.

When clicking on Monitor, however, all I get is an error “serial port temporarily busy”. This is so no matter which sketch I run, e.g. the unchanged ASCII table sketch.

Screenshot attached.

Is there something wrong with the Arduino, or my PC, or do I have to set something up first?

From the screenshot it looks like you are still uploading the sketch on the board (busy button on top). Please also be sure not to have the serial monitor open in the desktop IDE or other softwares

Thanks. Yes, I wondered why the Busy button was active. It remained in this state forever, although the program was running already.

Three hours later, there is no problem. There is no Busy button, and I can access the console.

A glitch, I would say.