xamarin forms prism white screen - xamarin.forms

Question

On Xamarin Forms I am using Prism MVVM.
After doing some update these two package Microsoft.AspNetCore.SignalR.Client 1.1.0->3.0.0 and Microsoft.Extensions.Caching.Memory 2.2.0->3.0.0 my application showing only white screen.
Can not see login page.
I only update these two package. Deleted bin and obj folder and it did not help
Other packages version:
Prism.Forms-> 7.2.0.1367
Xamarin.Forms ->4.2.0.815419
Any idea ?
EDIT:
All package I am using :
<ItemGroup>
<PackageReference Include="Microsoft.AspNetCore.SignalR.Client">
<Version>1.1.0</Version>
</PackageReference>
<PackageReference Include="Microsoft.Extensions.Caching.Memory">
<Version>3.0.0</Version>
</PackageReference>
<PackageReference Include="NdefLibrary">
<Version>4.1.0</Version>
</PackageReference>
<PackageReference Include="Prism.Core">
<Version>7.2.0.1367</Version>
</PackageReference>
<PackageReference Include="Prism.Forms">
<Version>7.2.0.1367</Version>
</PackageReference>
<PackageReference Include="Prism.Plugin.Popups">
<Version>7.2.0.573</Version>
</PackageReference>
<PackageReference Include="Prism.Unity.Forms">
<Version>7.2.0.1367</Version>
</PackageReference>
<PackageReference Include="Rg.Plugins.Popup">
<Version>1.1.5.188</Version>
</PackageReference>
<PackageReference Include="System.Buffers">
<Version>4.5.0</Version>
</PackageReference>
<PackageReference Include="System.Memory">
<Version>4.5.3</Version>
</PackageReference>
<PackageReference Include="Xam.Plugins.Notifier">
<Version>3.0.1</Version>
</PackageReference>
<PackageReference Include="Xamarin.Android.Support.Design" Version="28.0.0.3" />
<PackageReference Include="Xamarin.Android.Support.v7.AppCompat" Version="28.0.0.3" />
<PackageReference Include="Xamarin.Android.Support.v4" Version="28.0.0.3" />
<PackageReference Include="Xamarin.Android.Support.v7.CardView" Version="28.0.0.3" />
<PackageReference Include="Xamarin.Android.Support.v7.MediaRouter" Version="28.0.0.3" />
<PackageReference Include="Xamarin.Essentials">
<Version>1.3.1</Version>
</PackageReference>
<PackageReference Include="Xamarin.Forms" Version="4.2.0.815419" />
<PackageReference Include="Xamarin.Forms.Visual.Material">
<Version>4.2.0.815419</Version>
</PackageReference>
<PackageReference Include="Xamarin.HotReload">
<Version>1.4.19</Version>
</PackageReference>
<PackageReference Include="ZXing.Net.Mobile">
<Version>2.4.1</Version>
</PackageReference>
<PackageReference Include="ZXing.Net.Mobile.Forms">
<Version>2.4.1</Version>
</PackageReference>
</ItemGroup>
EDIT : Found new error
Now I am getting these error. I got this error first removed signalR and readded it and checked the all "Common Language Runtime Exceptions"
System.TypeLoadException: 'Could not load type of field
'Microsoft.AspNetCore.Http.Features.Authentication.HttpAuthenticationFeature:<Handler>k__BackingField' (1)
due to: Could not resolve type with token 01000080 from typeref (
expected class 'Microsoft.AspNetCore.Http.Features.Authentication.IAuthenticationHandler' in assembly
'Microsoft.AspNetCore.Http.Features, Version=2.2.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60')
assembly:Microsoft.AspNetCore.Http.Features, Version=2.2.0.0, Culture=neutral,
PublicKeyToken=adb9793829ddae60 type:Microsoft.AspNetCore.Http.Features.Authentication.IAuthenticationHandler
member:(null)'
in debug windows
**System.TypeLoadException:** 'Could not load type of field 'Microsoft.AspNetCore.Http.Features.Authentication.HttpAuthenticationFeature:<Handler>k__BackingField' (1) due to: Could not resolve type with token 01000080 from typeref (expected class 'Microsoft.AspNetCore.Http.Features.Authentication.IAuthenticationHandler' in assembly 'Microsoft.AspNetCore.Http.Features, Version=2.2.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60') assembly:Microsoft.AspNetCore.Http.Features, Version=2.2.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60 type:Microsoft.AspNetCore.Http.Features.Authentication.IAuthenticationHandler member:(null)'
**System.Reflection.TargetInvocationException:** 'Exception has been thrown by the target of an invocation.'
**Unity.ResolutionFailedException:** 'For more information add Diagnostic extension: Container.AddExtension(new Diagnostic())'
**Prism.Navigation.NavigationException:** 'An error occurred while resolving the page. This is most likely the result of invalid XAML or other type initialization exception'
**Prism.Navigation.NavigationException:** 'An error occurred while resolving the page. This is most likely the result of invalid XAML or other type initialization exception'

Answer 1

In the pages code behind wrap the initialiseComponent() in a try catch and see what the error is with a breakpoint. White screen usually means Xaml issue