.NET Core 3.0 Preview 7 - Blazor App - GET /_framework/blazor.boot.json (similar to #1469)

[bartczernicki]

#11897 Describe the bug
404 Error - GET /_framework/blazor.boot.json (Similar to #1469)

To Reproduce

Steps to reproduce the behavior:

1. Using this version of ASP.NET Core '.Net Core 3.0 Preview 7 with new SignalR NuGet'

2. Run this code:
   https://github.com/bartczernicki/MachineLearning-BaseballPrediction-BlazorApp
   Deployed here (App Service with SignalR)
   https://baseballpredictionblazor.azurewebsites.net/baseballprediction

3. With these arguments: Select the fake player or move slider. Sometimes on first load in 'preview 7' it just hangs and requires a Ctrl+F5 reload

4. See error

Expected behavior

No hanging app on first load

Additional context

Don't remember this happening in preview 6 or earlier. But then again App Insights with Blazor had issues (it would just stop working). Preview 7 .net core 3.0 it works fine.

I work at Microsoft, so can debug internally as well.

[mkArtakMSFT]

Thanks for contacting us, @bartczernicki.
We're heads down finalizing the upcoming 3.0 release and we'll be able to look into this post 3.0.

[pranavkm]

@bartczernicki it's fairly likely you were running in to #11560. I tried playing around with your deployed application now and could not reproduce the error.