“Error: The username field is empty.”

I am currently working on a project with Ionic / Angular, and when sending the POST data to get the token, I am getting that error.

message: “Error: The username field is empty.”

logForm(){
    let user: User = {
      "username": this.loginForm.value.username,
      "password": this.loginForm.value.password
    }
    this._qService.login(user);
  }

That is the method of my component class in Ionic

public login(user: User) {
    let url = ${environment.jwt};
    return this.http.post(url, user).subscribe((resp: any) => {
      console.log(user);
      console.log(resp);
      if (resp.success && resp.statusCode === 200) {
        this.router.navigate(['/topics']);
        return this.saveStorage(resp.token, resp.id);
      }
      if (resp.success === false && resp.statusCode === 403) {
        const msg = 'Incorrect data'
        this.logError(msg);
      }
    })
  }

That is the service where I do the POST to the endpoint