Error in http Ionic to an api de laravel

If anyone knows what the problem is, I need help for my ionic 3 application that calls a laravel api. It works correctly when you run my ionic application from the web, calling localhost: 8000 / api / employees, however I need to run the application from a device, so change localhost to the ip where the laravel project is running, presents the following error.

Failed to load resource: net :: ERR_CONNECTION_TIMED_OUT Could not get any response.

my code is as follows:

import { HttpClient } from '@angular/common/http';
import { Injectable } from '@angular/core';

@Injectable()
export class RestapiProvider {
  url: string = "http://192.168.234.141:8000/api/empleados";
//localhost:8000/api/empleados
  constructor(public http: HttpClient) {
    console.log('Hello RestapiProvider Provider');
  }

  getUsers(){
   return new Promise(resolve => {
     this.http.get(this.url).subscribe( data => {
       resolve(data);
     }, err => {
       console.log(err);
     });
   });
  }

  addUser(data) {
    return new Promise((resolve, reject) => {
      this.http.post(this.url+'/api/empleados', JSON.stringify(data))
        .subscribe(res => {
          resolve(res);
        }, (err) => {
          reject(err);
        });
    });
  }

}

Thank you very much to anyone who can answer.