401 (Unauthorized) error when create a post

[aymangithub]

please.
I have an 401 (Unauthorized) error when I create a post

error: https://localhost/hl-bir/wp-json/wp/v2/posts 401 (Unauthorized)

and this is the function:

createPost(body: any) {
let headers = new Headers();
headers.append('Content-Type', 'application/json;charset=UTF-8');
headers.append('Access-Control-Allow-Origin', '*');
headers.append('Access-Control-Allow-Headers', 'Content-Type, Content-Range, Content-Disposition, Content-Description');
headers.append('Access-Control-Allow-Methods', 'DELETE, HEAD, GET, OPTIONS, POST, PUT');
headers.append('Authorization', 'Basic ' + btoa('username:password'));
headers.append('Cache-Control', 'no-cache');
this.wpApiPosts.create(body, headers)
.toPromise()
.then(response => response.json())
.then(res => {
console.log(res);
})
.catch(err => {
console.log(err);
});
}

this.wpProvider.createPost(
  { titte: 'MyPost3', status: 'publish' }
);

---

Note that there is no problem in creating a new post from the URL in the chrome browser using the plugin JSON API
https://localhost/hl-bir/api/create_post/?nonce=5bee184120&title=mypost4&status=publish

Thanks in advance