xamarin.auth with google UriFormatException

Question

I want to login to google Account by xamarin.auth and follow this Microsoft tutorial but i show this error System.UriFormatException: 'Invalid URI: The format of the URI could not be determined.'

when Run on Android device and ios simulator

Update =>

As @Jason Said {if you are getting an "invalid URI" exception, then it stands tor reason that one of your URI arguments is invalid.}

its my mistak i forgot to add {:/oauth2redirect}

Thank you @Jason Thank you @Paul Kertscher