HTTP Post in iOS not working

HI I am trying for http post request in iOS but its not working and giving error

both angular http and ionic http not for POST request in iOS.

Error Response is


My Post Request

const httpOptions = {
headers: new HttpHeaders({
‘Authorization’: Authorization,
‘Content-type’ : ‘application/json’,

const body = new HttpParams()
.set(‘grant_type’, ‘authorization_code’)
.set(‘client_id’ , this.client_id)
.set(‘redirect_uri’, this.redirect_url)
(response) => {
console.log(‘Token recived------------’+response);
(error) => {
if (error.error instanceof ErrorEvent) {
// A client-side or network error occurred. Handle it accordingly.
console.error(‘An error occurred:’, error.error.message);
} else {

    // The backend returned an unsuccessful response code.
    // The response body may contain clues as to what went wrong,
      `Backend returned code ${error.status}, ` +
      `body was: ${error.error}`);

Can anybody tell my mistake.