GULP Browsersync does not start

I have a gulpfile.js with this code:

var gulp = require('gulp'),
less = require('gulp-less'),
path_less = require('path'),
browserSync = require('browser-sync').create();

var path = {...paths...};

gulp.task('less', function(done){
    gulp.src(path.src.def + path.src.less + '*.less')
        .pipe(less({paths: [ path_less.join(__dirname, 'less', 'includes') ]}))
        .pipe(gulp.dest(path.dev.def + path.dev.css))
        .pipe(browserSync.stream());

    done();
});
gulp.task('serve', gulp.series('less'), function(done){
    browserSync.init({
        server: './',
        proxy : 'belaz.dev'
    });

    gulp.watch(path.src.def + path.src.less + '*.less', gulp.series('less'))
    gulp.watch(path.dev.def + path.dev.css + '*.css').on('change', browserSync.reload());

    done();
});

gulp.task('default', gulp.series('serve'), function(done){
    done();
});

When i run Gulp browsersync doesn't do anything - all tasks starts, ends and nothing happens

How or why? And how i could fix it