Ionic v4 : HttpErrorResponse!

hello,
please i need your help … i am trying to get data from REST API and i get that error !

i am using ionic v4

service.ts

import { Injectable } from '@angular/core';
import { HttpClient, HttpParams, HttpHeaders } from '@angular/common/http';
import { Observable } from 'rxjs';
import { map } from 'rxjs/operators';


@Injectable({
  providedIn: 'root'
})
export class LoginService {

  

  constructor(private http: HttpClient) {
  }

  // service that test if the user exist or not
  authentification(user:string,password:string):Observable<any>{

   

    const headers = new HttpHeaders({
      'Content-Type': 'application/json',
      'JsonStub-User-Key': '732e939b-05b7-4877-8d8f-f924e67638eb',
      'JsonStub-Project-Key': '31ec72a8-2779-4931-843f-1cbd37b81b2c',
      "Access-Control-Allow-Headers" : "*"
    });
    return this.http.get('http://jsonstub.com/enova_sante_app/api/services/patient',{headers,responseType: 'json'})
        .pipe(map(data => {

          //console.log(data.status);
          console.log(data); // data received by server
          //console.log(data.headers);
          return data;
          
        },
        (error: any) => {
            console.log(error);
        }));
    
  }


}

Looks like the API is not returning JSON. Make sure the API has the following header,

'Content-Type application/json'

@patrick-ulster that what the API returning

Click on the Raw tab and show me what is being returned.

In chrome can you go to the network tab and show me the response from the API?

thank you so much for your time
now it’s working with me after i restart my computer and i open it in a private chrome window.