Cannot Resolve type "DateTime"

Question

I am trying to get my API working for an app I am building in Xamarin Forms, but I am having trouble with getting the DateTime to work. I keep receiving an error XFC0000: Cannot resolve type "DateTime". I cannot figure out how to fix this error and have searched everywhere I can to get this resolved.

 <ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml" xmlns:ob="clr-namespace:Sweater_Weather_2.ViewModels"
             x:Class="Sweater_Weather_2.Views.WeatherPage">
    
    <ContentPage.BindingContext>
        <ob:WeatherViewModel/>
    </ContentPage.BindingContext>

    <CollectionView ItemsSource="{Binding WeatherList}">
        <CollectionView.ItemsLayout>
            <GridItemsLayout  Orientation="Vertical" />
        </CollectionView.ItemsLayout>
        <CollectionView.ItemTemplate>
            <DataTemplate>
                <StackLayout Padding="10">
                    <Grid>
                        <Grid.RowDefinitions>
                            <RowDefinition Height="Auto"/>
                            <RowDefinition Height="Auto"/>
                            <RowDefinition Height="Auto"/>
                            <RowDefinition Height="Auto"/>
                        </Grid.RowDefinitions>

                        <Grid Grid.Row="0" BackgroundColor="#E9E9E5" >
                            <Label Grid.Row="0" Grid.Column="0" Text="{Binding timezone}" FontSize="20" FontAttributes="Bold" TextColor="#52524E"/>
                            <Label Grid.Row="1" Grid.Column="0" Text="{Binding Source={x:Static sys:DateTime.Now}, StringFormat='{0:MMMM dd, yyyy}'}"/>
                        </Grid>

Any help would be appreciated, if more coded is needed please let me know.