Q:

Xamarin.iOS can convert latlong to address with error com.google. HTTPStatus error 400

I need to convert my Latitude and longitude to address to extract so data from it 
here is my method but this fail with error {The operation couldn’t be completed. ( com.google. HTTPStatus error 400.)}  
void ConvertLatLong(double latitude, double longitude)
        {
            try
            {
                Geocoder geocoder;
                CLLocationCoordinate2D location = new CLLocationCoordinate2D(latitude, longitude);

                geocoder = new Geocoder();

                geocoder. ReverseGeocodeCord(location ,(response, error) => {

                    if (error ! = null) return;

                    var addresses = response. Results;
                    if (addresses ! = null && addresses. Length > 1)
                    {
                      Address selectedAddress = addresses[1];
                      if (selectedAddress. AdministrativeArea ! = null)
                      {
                            var citySelected = citiesLookupResult. Find(c => (selectedAddress. AdministrativeArea. Contains(c. NameEn)));
                            chooseCity. Text = citySelected. NameEn;
                      }
                    }

                });

            }
            catch (Exception e)
            {

            }
        }

my tries to fix this issue 
First I make sure that my bundle name is matched between google console and my application 
Second  make sure I set my E-mail , app name under Credential --> oAuth consent screen
any one could help me with my issue 
 

A:

Possible solutions 

Enable GoogleMap SDK for iOS Here
Register Api key for GMSServices in didFinishLaunchingWithOptions. 
Check that your API key is valid for your bundle id on console.developer.google.com.