unable to navigate the content page when i click on button using xamarin forms

Im unable to navigate the content page when i click on button using xamarin forms. It is working on Android but not working in IOS.

Kindly check the below code.
ButtonClick Event

Navigation.PushAsync(new LeaveRequestAddEdit("insert"));

The xaml code is

    <?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"

    <ContentPage.Content>
        <StackLayout>
            <Frame Padding="5" Margin="5,5,5,5" CornerRadius="10" HasShadow="True" BackgroundColor="White" BorderColor="LightBlue">
                <Grid BackgroundColor="White" x:Name="LeaveRequestContainer">
                    <Grid.RowDefinitions>
                        <RowDefinition Height="Auto"/>
                        <RowDefinition Height="Auto"/>
                        <RowDefinition Height="Auto"/>
                        <RowDefinition Height="Auto"/>
                        <RowDefinition Height="Auto"/>
                    </Grid.RowDefinitions>
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="*" />
                        <ColumnDefinition Width="*" />
                    </Grid.ColumnDefinitions>
                    <StackLayout Grid.Row="0" Grid.Column="0" Orientation="Horizontal">
                        <RadioButton x:Name="OnedayRadioBtn"  Clicked="OnedayRadioBtn_Clicked" />
                        <Label Text="One Day" HorizontalTextAlignment="Center" VerticalTextAlignment="Center"/>
                    </StackLayout>
                    <StackLayout Grid.Row="0" Grid.Column="1" Orientation="Horizontal">
                        <RadioButton  x:Name="MultipledaysRadioBtn"  Clicked="MultipledaysRadioBtn_Clicked"/>
                        <Label Text="Multiple Days" HorizontalTextAlignment="Center" VerticalTextAlignment="Center"/>
                    </StackLayout>
                    <Label x:Name="selectlable"  Text="Select          :" Margin="50,0,0,0" IsVisible="False" Grid.Row="1" Grid.Column="0" HorizontalOptions="StartAndExpand" VerticalTextAlignment="Center" HorizontalTextAlignment="Center"/>
                    <DatePicker x:Name="selectdate" IsVisible="False" Date="{Binding FromDate,Mode=TwoWay}"  Format="dd/MM/yyy" Grid.Row="1" Grid.Column="1" HorizontalOptions="StartAndExpand" />
                    <Label  x:Name="fromdatelabel" Text="From Date        :" IsVisible="False" Margin="50,0,0,0" Grid.Row="1" Grid.Column="0" HorizontalOptions="StartAndExpand" VerticalTextAlignment="Center" HorizontalTextAlignment="Center"/>
                    <DatePicker x:Name="fromdate" IsVisible="False" DateSelected="fromdate_DateSelected" Date="{Binding FromDate,Mode=TwoWay}"  Format="dd/MM/yyy" Grid.Row="1" Grid.Column="1" HorizontalOptions="StartAndExpand"/>
                    <Label x:Name="todatelable" Text="To   Date           :" IsVisible="False" Margin="50,0,0,0" Grid.Row="2" Grid.Column="0" HorizontalOptions="StartAndExpand" VerticalTextAlignment="Center" HorizontalTextAlignment="Center"/>
                    <DatePicker x:Name="Todate" IsVisible="False" Date="{Binding ToDate,Mode=TwoWay}"  Format="dd/MM/yyy" Grid.Row="2" Grid.Column="1" HorizontalOptions="StartAndExpand"/>
                    <Frame CornerRadius="10" Margin="0" Padding="0" BorderColor="LightBlue" Grid.Row="3" Grid.Column="0" Grid.ColumnSpan="2" >
                        <local1:ExtendedEditorControl  x:Name="Reason" Placeholder="Enter Reason Here" IsExpandable="True"  Text="{Binding ReasonForLeave,Mode=TwoWay}"   VerticalOptions="FillAndExpand" HorizontalOptions="FillAndExpand"  MaxLength="250" />
                    </Frame>
                    <StackLayout Orientation="Vertical" x:Name="ActionNoteStack" IsVisible="False"  Grid.Row="4" Grid.ColumnSpan="2" Grid.RowSpan="2">
                        <Label  x:Name="title" IsVisible="False" Text="Action Notes :" TextColor="Black"  HorizontalOptions="Start" VerticalOptions="Center" />
                        <!--<Label Text="Action Notes :" WidthRequest="400" VerticalTextAlignment="Center" HorizontalOptions="FillAndExpand" TextColor="Blue"/>-->
                        <Frame x:Name="actionframe" IsVisible="False"  CornerRadius="10" Margin="0" BorderColor="LightBlue"  Padding="0">
                            <Label x:Name="actionNote" IsVisible="False" Text="{Binding ActionNotes,Mode=TwoWay}" Margin="5"   VerticalOptions="Center" HorizontalOptions="FillAndExpand"  />
                        </Frame>
                    </StackLayout>
                </Grid>
            </Frame>
            <StackLayout Margin="5,0,5,5" Orientation="Horizontal"  VerticalOptions="End">
                <Button Text="Save" x:Name="btnSave"  BackgroundColor="#6559D8" CornerRadius="10" TextColor="White"  HorizontalOptions="FillAndExpand" Clicked="btnSave_Clicked"/>
                <Button Text="Cancel" x:Name="btnCancel" Clicked="btnCancel_Clicked"  BackgroundColor="Gray"  CornerRadius="10" TextColor="White"  HorizontalOptions="FillAndExpand"/>
            </StackLayout>
        </StackLayout>
    </ContentPage.Content>
</ContentPage>

Kindly help on this. I'm new to Xamarin forms