Incorrect callback?

Hi I;m trying to implement Okta on xamarin forms. I can get to the Okta login screen, but after logging in, I am not returned to the mobile app. Instead I end up on the webste screen:

I am using OAuth2Authenticator to login, the code snippet looks like this:
var authenticator = new AuthenticatorExtensions(
clientId: OktaConfiguration.ClientId,
scope: OktaConfiguration.Scopes,
authorizeUrl: new Uri(OktaConfiguration.OrganizationUrl),
redirectUrl: new Uri(redirectUrl),
getUsernameAsync: null,
isUsingNativeUI: false);

        var Presenter = new Xamarin.Auth.Presenters.OAuthLoginPresenter();
        authenticator.Completed += OktaAuthenticator_Completed;
        authenticator.Error += (s, e) =>


Unfortunately, it never returns, so neither the error or the authenticator.Completed is ever called.

the redirectUri is per my applications login redirect uri: