Why doesn't Gulp browser-sync open the browser?

Question

Why doesn't Gulp browser-sync open the browser?

When I write Gulp watch, all functions work except browser-sync. I tried to disable the antivirus, but without results.

const gulp = require('gulp');
const autoprefixer = require('gulp-autoprefixer');
const cleanCSS = require('gulp-clean-css');
var browserSync = require('browser-sync').create();

let config = {
    src: 'src',
    css: {
        src: '/precss/**/*.css',
        dest: '/css'
    }
};

gulp.task('build', function() {     
    gulp.src(config.src + config.css.src)               
        .pipe(autoprefixer({                                
            browsers: ['last 2 versions'],
            cascade: false
        }))
        .pipe(cleanCSS())
        .pipe(gulp.dest(config.src + config.css.dest))                   
        .pipe(browserSync.reload({
            stream: true
        }));
});

gulp.task('watch', ['browserSync'],  function() {               
   gulp.watch(config.src + config.css.src, ['build']);        
});

gulp.task('browserSync', function() {
    browserSync.init({
        server: {
            baseDir: config.src                         
        }
    });
});

Answer 1

The answer is not at all obvious. I was able to do it when I start the terminal without administrator rights. No code corrections