var output=this.loginService.IsLogin(Username, Password).subscribe();

var output=this.loginService.IsLogin(Username, Password).subscribe();

if (output == true) {
  this.router.navigate(['/incidentSupport'])
}
else if (userName.trim() == "" && password.trim() == "")
{
  this.msg = "Please enter the username or Password"
}
else
{
  this.msg = "Invalid username or password"
}

fetchList(start: string, end: string): Observable<Object> {
    return this.http.get(URL)
}

this.loginService.IsLogin(Username, Password).subscribe((resp: any) => {
  // This assumes that your API directly returns a boolean
  if(output) {
    this.router.navigate(['/incidentSupport']);
  }
  else if(userName.trim() == "" && password.trim() == "") {
    this.msg = "Please enter the username or Password"
  }
  else {
    this.msg = "Invalid username or password"
  }
});