What is the URL of the page with the issue?

https://go.dev/play/

What is your user agent?

Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Firefox/91.0

Screenshot

What did you do?

I was reading the Inside the Go Playground - The Go Programming Language blog, and wanted to try an example that was listed there about network. When I tried the example, more often I encountered the error that can be seen in second image, than the actual result that can be seen in the first image.

I'm sorry if it's wrong to report this issue here but I saw no option to report playground issues on the website.

Code that I tested:

package main

import (
	"io"
	"log"
	"net"
	"os"
)

func main() {
	l, err := net.Listen("tcp", "127.0.0.1:4000")
	if err != nil {
		log.Fatal(err)
	}
	defer l.Close()

	go dial()

	c, err := l.Accept()
	if err != nil {
		log.Fatal(err)
	}
	defer c.Close()

	io.Copy(os.Stdout, c)
}

func dial() {
	c, err := net.Dial("tcp", "127.0.0.1:4000")
	if err != nil {
		log.Fatal(err)
	}
	defer c.Close()
	c.Write([]byte("Hello, network\n"))
}