Unable to debug Blazor hosted webassembly 5.0.2 from Visual Studio 2019 16.8.4

[pmeems]

Describe the bug

I'm running into the same issues as reported in #22911
I'm running v5.0.200-preview.20614.14, using VS Studio 2019 Community v16.8.4
I have the same issues when running VS Studio 2019 Community Preview v16.9.0 Preview 3.0
When hitting F5 in VS the blank about page is opened and nothing is loaded.
When manually type in https://localhost:44356/ the app starts.
This happens when opened in Chrome and in Edge.
When opening in IE I get these Javascript errors:

• JavaScript critical error at line 1, column 1399 in https://localhost:44356/_content/Microsoft.Authentication.WebAssembly.Msal/AuthenticationService.js\n\nSCRIPT1002: Syntaxis Error
• JavaScript critical error at line 1, column 1723 in https://localhost:44356/_framework/blazor.webassembly.js\n\nSCRIPT1002: Syntaxis Error

To Reproduce

I just started a fresh Blazor WASM app running the tutorial at https://docs.microsoft.com/en-us/aspnet/core/blazor/security/webassembly/hosted-with-azure-active-directory-b2c?view=aspnetcore-5.0
Basically the command I used is:
dotnet new blazorwasm -au IndividualB2C --aad-b2c-instance "{AAD B2C INSTANCE}" --api-client-id "{SERVER API APP CLIENT ID}" --app-id-uri "{SERVER API APP ID URI}" --client-id "{CLIENT APP CLIENT ID}" --default-scope "{DEFAULT SCOPE}" --domain "{TENANT DOMAIN}" -ho -o {APP NAME} -ssp "{SIGN UP OR SIGN IN POLICY}"

Further technical details

• ASP.NET Core version: v5.0.200-preview.20614.14
• Include the output of dotnet --info

.NET SDK (reflecting any global.json):
Version: 5.0.200-preview.20614.14
Commit: 863605c8c3

Runtime Environment:
OS Name: Windows
OS Version: 10.0.19042
OS Platform: Windows
RID: win10-x64
Base Path: C:\Program Files\dotnet\sdk\5.0.200-preview.20614.14\

Host (useful for support):
Version: 5.0.2
Commit: cb5f173b96

.NET SDKs installed:
2.1.520 [C:\Program Files\dotnet\sdk]
2.1.812 [C:\Program Files\dotnet\sdk]
2.2.300 [C:\Program Files\dotnet\sdk]
2.2.401 [C:\Program Files\dotnet\sdk]
3.1.100-preview3-014645 [C:\Program Files\dotnet\sdk]
3.1.200-preview-015002 [C:\Program Files\dotnet\sdk]
3.1.300-preview-015048 [C:\Program Files\dotnet\sdk]
3.1.300-preview-015095 [C:\Program Files\dotnet\sdk]
5.0.100-rc.1.20452.10 [C:\Program Files\dotnet\sdk]
5.0.100 [C:\Program Files\dotnet\sdk]
5.0.101 [C:\Program Files\dotnet\sdk]
5.0.102 [C:\Program Files\dotnet\sdk]
5.0.200-preview.20614.14 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
Microsoft.AspNetCore.All 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.15 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.16 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.17 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.20 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.21 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.22 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.23 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.24 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.2.5 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.2.6 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.App 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.15 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.16 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.17 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.20 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.21 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.22 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.23 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.24 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.2.5 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.2.6 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.1.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.1.11 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 5.0.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 5.0.1 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 5.0.2 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.NETCore.App 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.15 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.16 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.17 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.20 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.21 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.22 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.23 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.24 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.2.5 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.2.6 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.1.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.1.11 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 5.0.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 5.0.1 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 5.0.2 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.WindowsDesktop.App 3.1.9 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 3.1.11 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 5.0.0 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 5.0.1 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 5.0.2 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

• The IDE (VS / VS Code/ VS4Mac) you're running on, and its version
  Tried with VS Studio 2019 Community v16.8.4 and VS Studio 2019 Community Preview v16.9.0 Preview 3.0

[javiercn]

@pmeems thanks for contacting us.

Something weird is going on with the VS Debugger I think. @captainsafia do you know who the right folks to talk about this are?

I would suggest you close VS and try to remove the .vs folder to see if that helps

[pmeems]

Thanks @javiercn I just closed VS, deleting the .vs folder and tried again.
The same result. Only the About page is shown and after a while VS reports an error.

[captainsafia]

Thanks for the info, @pmeems. It looks like you've identified two different issues in the PR.

The first is the webpage not automatically loading after pressing F5 and the second is the error you receive when opening in IE.

• Are you able to debug after manually navigating to the webpage?
• What version of IE were you trying to use in the second half?

[javiercn]

I didn't realize the IE part.

Current versions of Blazor don't support Internet Explorer. Only Microsoft Edge.

[captainsafia]

@javiercn Ah, right you are. I always get groggy on our supportability matrix. But luckily there's a website for that: https://docs.microsoft.com/en-us/aspnet/core/blazor/supported-platforms?view=aspnetcore-5.0.

Another thing I'd recommend is to see if you can reproduce the issue with debugging when starting the app on a Kestrel server.