my app stores my token, but I can’t send it to the header

I get the following error when I put validaToken () at login, the token is stored correctly in local storage.

I put in de server, but it does not work :

 server.app.use( bodyParser.urlencoded({ extended:true }) );
    server.app.use( bodyParser.json());
    server.app.use((req, res, next) => {
        res.setHeader("Access-Control-Allow-Origin", "*");
        res.setHeader("Access-Control-Allow-Credentials", "true");
        res.setHeader("Access-Control-Allow-Methods", "GET,HEAD,OPTIONS,POST,PUT");
        res.setHeader("Access-Control-Allow-Headers", "Access-Control-Allow-Headers, Origin,Accept, X-Requested-With, Content-Type, Access-Control-Request-Method, Access-Control-Request-Headers");
        next();
    });

console error

frontend code

usuario.service:

  async validaToken() {

    const headers = new HttpHeaders({
      'x-token': this.token
    });

    return new Promise( resolve => {

      console.log(headers);

      this.http.get(`${ URL }/user/`, { headers })
          .subscribe( resp => {

            if ( resp['ok'] ) {
              this.usuario = resp['usuario'];
              console.log(this.usuario);
              resolve(true);
            } else {
              this.navCtrl.navigateRoot('/login');
              resolve(false);
            }

          });

    });

  }

Source: Angular Questions