Unhandled Exception: Platform

[Miles-Ahead-Digital]

Hi,
if I login to a client a second time. I get this stacktrace at await launch(url, forceWebView: true); - but the logon still works.
I'm testing on iOS.

[VERBOSE-2:ui_dart_state.cc(177)] Unhandled Exception: PlatformException(Error, Error while launching https://keycloak.miles-ahead.cloud:8443/auth/realms/flutter/protocol/openid-connect/auth?response_type=code&scope=openid+&client_id=flutter&redirect_uri=http%3A%2F%2Flocalhost%3A4000%2F&state=OX4JNHvT2vHs6ZWsCxC39AVHcex3WBQ5SGR6bxfDB2CA9MzW39&code_challenge_method=S256&code_challenge=ChNV82Y-d4nt8QqdIL8t8Gb5X0ZxgBb43ZnkF-DL-fE, null, null)
#0      StandardMethodCodec.decodeEnvelope (package:flutter/src/services/message_codecs.dart:582:7)
#1      MethodChannel._invokeMethod (package:flutter/src/services/platform_channel.dart:159:18)
<asynchronous suspension>
#2      launch (package:url_launcher/url_launcher.dart:95:23)
<asynchronous suspension>
#3      OpenIdStore.signIn.<anonymous closure> (package:openid_client_master/src/blocs.dart:141:9)
<asynchronous suspension>

Future<UserInfo> signIn(Map<String, dynamic> clientInfo) async {
    print(" signIn started");
    var uri = Uri.parse(clientInfo["issuer"]);
    var issuer = await Issuer.discover(uri);
    var client = new Client(
      issuer,
      clientInfo["client_id"],
    );
    print(' signIn   $clientInfo["redirect_uri"]');
    var authenticator = new Authenticator(client,
        scopes: clientInfo["scopes"].split(","),
  //      redirectUri: clientInfo["redirect_uri"] == null
  //          ? null
  //          : Uri.parse(clientInfo["redirect_uri"]),
        port: 4000, urlLancher: (url) async {
      if (await canLaunch(url)) {
        await launch(url, forceWebView: true);
      } else {
        throw 'Could not launch $url';
      }
    });

How can we improve the code to avoid this error (better then just ignoring it with an empty try catch surrounding)?

Best regards
Stefan