node.js, css validation, w3c banned me?

I apologize in advance for what I write through a translator, I am very bad at English.

I was faced with the following problem: I need to perform validation css files. To this end, I decided to use the NPM package w3c-css, first it worked, but then start giving "connected etimedout", in the course of research, I noticed that through the browser and the validator stops working.

Sniffer log at start of my script: link (<10 rep :( )

My code:

gulp.task('css', function() {
  gulp.src('dev/sass/*.scss')
    .pipe(through2.obj(function(file, enc, cb){
      w3c_css.validate({text: file.contents.toString('utf8')}, function(err, data) {
        if(err) {
          // an error happened
          console.error(err);
        } else {
          // validation errors
          console.log('validation errors', data.errors);

          // validation warnings
          console.log('validation warnings', data.warnings);
        }

      });
      cb(null, file);
    }))
    .pipe(gulp.dest('build/'));
});

What is the reason? It must be some mistake, or I block due to too frequent requests and it does not change? Maybe there is some other way to check the css files?

Thx!