The browser is stuck with error "WebSocket connection to 'wss://localhost:65041/' failed:" after dotnet watch for Blazor Web App ~ Server ~Global

[Susie-1989]

REGRESSION INFO: Repro on 9.0.308

INSTALL STEPS

1. OS: window x64
2. Install the SDK 10.0.101

REPRO STEPS

1. Open up a normal Command Prompt (Terminal)
2. Create Blazor Web App ~ Server ~Global

  dotnet new blazor -ai true -o blazor11
  cd blazor11
  dotnet watch

3. Open Home.razor and modify the code and save this file.

Note:

1. After refresh the browser, it will work.
2. This issue works well for Blazor Web App ~ Server ~ Per page/component
3. This issue works well for mvc /razor project
4. There is a similar issue 64051
   
   ACTUAL The browser is stuck and no response when clicking any button.

PageLogger::scheduleLogFlush - scheduling timer
mmr_main.js:1  17:43:29.431 MMRWarn: MMR readInjectionParameters: input parameter element missing.
Warn @ mmr_main.js:1
blazor.web.wmp8iwak4q.js:1 [2025-12-29T09:43:29.476Z] Information: Normalizing '_blazor' to 'http://localhost:5234/_blazor'.
blazor.web.wmp8iwak4q.js:1 [2025-12-29T09:43:29.502Z] Information: WebSocket connected to ws://localhost:5234/_blazor?id=dv1HiKt2_WcdqEM7vhGkIQ.
aspnetcore-browser-refresh.js:350  WebSocket connection to 'wss://localhost:65041/' failed: 
(anonymous) @ aspnetcore-browser-refresh.js:350
[NEW] Explain Console errors by using Copilot in Edge: click

C:\Users\v-yuwzh\blazor11>dotnet watch --verbose
dotnet watch ⌚ Working directory: 'C:\Users\v-yuwzh\blazor11'
dotnet watch ⌚ Watching with Hot Reload.
dotnet watch 🔥 Hot reload enabled. For a list of supported edits, see https://aka.ms/dotnet/hot-reload.
dotnet watch 💡 Press Ctrl+R to restart.
dotnet watch 🔨 Building C:\Users\v-yuwzh\blazor11\blazor11.csproj ...
dotnet watch 🚀 Launched 'C:\Program Files\dotnet\dotnet.exe' with arguments 'build C:\Users\v-yuwzh\blazor11\blazor11.csproj -consoleLoggerParameters:NoSummary;Verbosity=minimal --property:NuGetInteractive=true': process id 24796
dotnet watch ⌚ Process id 24796 ran for 6237ms and exited with exit code 0.
dotnet watch 🔨 Build succeeded: C:\Users\v-yuwzh\blazor11\blazor11.csproj
dotnet watch 🔨   Determining projects to restore...
dotnet watch 🔨   All projects are up-to-date for restore.
dotnet watch 🔨   blazor11 -> C:\Users\v-yuwzh\blazor11\bin\Debug\net10.0\blazor11.dll
dotnet watch 🔨
dotnet watch 🔨 Build succeeded.
dotnet watch 🔨     0 Warning(s)
dotnet watch 🔨     0 Error(s)
dotnet watch 🔨
dotnet watch 🔨 Time Elapsed 00:00:05.93
dotnet watch ⌚ Watching 66 file(s) for changes
dotnet watch ⌚ Exclusion glob: '**\node_modules\**;node_modules\**;**\jspm_packages\**;jspm_packages\**;**\bower_components\**;bower_components\**;**\packages.lock.json;bin\Debug\/**;obj\Debug\/**;bin\/**;obj\/**;**/*.user;**/*.*proj;**/*.sln;**/*.slnx;**/*.vssscc;**/.DS_Store' under project 'C:\Users\v-yuwzh\blazor11'
dotnet watch ⌚ Application kind: WebApplication.
dotnet watch 🔃 [blazor11 (net10.0)] Using browser-refresh middleware
dotnet watch 🔃 [blazor11 (net10.0)] Refresh server running at wss://localhost:65041,ws://localhost:65042.
dotnet watch ⌚ dotnet-watch is configured to launch a browser on ASP.NET Core application startup.
dotnet watch 🔥 [blazor11 (net10.0)] Waiting for application to connect to pipe a74f49db9b564dc3925d67c9b4d5a713.
dotnet watch 🚀 [blazor11 (net10.0)] Launched 'C:\Program Files\dotnet\dotnet.exe' with arguments 'run --no-build -e DOTNET_WATCH=1 -e DOTNET_WATCH_ITERATION=1 -e "HOTRELOAD_DELTA_CLIENT_LOG_MESSAGES=dotnet watch 🕵️ [blazor11 (net10.0)]" -e DOTNET_MODIFIABLE_ASSEMBLIES=debug -e "DOTNET_STARTUP_HOOKS=C:\Program Files\dotnet\sdk\10.0.101\DotnetTools\dotnet-watch\10.0.101\tools\net10.0\any\hotreload\net6.0\Microsoft.AspNetCore.Watch.BrowserRefresh.dll;C:\Program Files\dotnet\sdk\10.0.101\DotnetTools\dotnet-watch\10.0.101\tools\net10.0\any\hotreload\net10.0\Microsoft.Extensions.DotNetDeltaApplier.dll" -e DOTNET_WATCH_HOTRELOAD_NAMEDPIPE_NAME=a74f49db9b564dc3925d67c9b4d5a713 -e ASPNETCORE_AUTO_RELOAD_WS_ENDPOINT=wss://localhost:65041,ws://localhost:65042 -e ASPNETCORE_AUTO_RELOAD_WS_KEY=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAv72iPwmaQQscm3trK+9CKujoBB5Ul+nJr52ot2eyRW772SdFDqp5m8AKKFtHpa3POTFEbBW6PN/wHiLMI30oclSa/bWQil3dkW9fOBNF65m6pSS0wsCTjf/G7cKeELl4ZvsNq29Kbm5NTJRv2F5M9oo8FOCW/D/VcJLgupMXIlUBZLYCLEXqy160YAvc8jxPGqBh7MS/SAIBiMiVi6N+fM3mV3tQ1J4ED/xO9I8PDbAvGT1NbZGjt7YmXWHNXFex1vnB3U5N/7849dE5/a9EBEPNnhw3MeECqzkQ0K4Kn21CQK0HtUlp5q6jub2jReLk6c0rCgF0UnnsLT93aRNdUQIDAQAB -e ASPNETCORE_AUTO_RELOAD_VDIR=/ -e ASPNETCORE_HOSTINGSTARTUPASSEMBLIES=Microsoft.AspNetCore.Watch.BrowserRefresh -e Logging__LogLevel__Microsoft.AspNetCore.Watch=Debug': process id 12672
Using launch settings from C:\Users\v-yuwzh\blazor11\Properties\launchSettings.json...
dotnet watch 🕵️ [blazor11 (net10.0)] Loaded into process: C:\Users\v-yuwzh\blazor11\bin\Debug\net10.0\blazor11.dll (C:\Program Files\dotnet\sdk\10.0.101\DotnetTools\dotnet-watch\10.0.101\tools\net10.0\any\hotreload\net10.0\Microsoft.Extensions.DotNetDeltaApplier.dll)
dotnet watch 🕵️ [blazor11 (net10.0)] Windows Ctrl+C handling enabled.
dotnet watch 🕵️ [blazor11 (net10.0)] Connecting to hot-reload server via pipe a74f49db9b564dc3925d67c9b4d5a713
dotnet watch 🕵️ [blazor11 (net10.0)] Connected.
dotnet watch 🔥 [blazor11 (net10.0)] Capabilities: 'Baseline AddMethodToExistingType AddStaticFieldToExistingType AddInstanceFieldToExistingType NewTypeDefinition ChangeCustomAttributes UpdateParameters GenericUpdateMethod GenericAddMethodToExistingType GenericAddFieldToExistingType AddFieldRva'.
dbug: Microsoft.AspNetCore.Watch.BrowserRefresh.BlazorWasmHotReloadMiddleware[0]
      Middleware loaded
dbug: Microsoft.AspNetCore.Watch.BrowserRefresh.BrowserScriptMiddleware[0]
      Middleware loaded. Script /_framework/aspnetcore-browser-refresh.js (16481 B).
dbug: Microsoft.AspNetCore.Watch.BrowserRefresh.BrowserScriptMiddleware[0]
      Middleware loaded. Script /_framework/blazor-hotreload.js (799 B).
dbug: Microsoft.AspNetCore.Watch.BrowserRefresh.BrowserRefreshMiddleware[0]
      Middleware loaded: DOTNET_MODIFIABLE_ASSEMBLIES=debug, __ASPNETCORE_BROWSER_TOOLS=true
info: Microsoft.Hosting.Lifetime[14]
      Now listening on: http://localhost:5234
dotnet watch ⌚ Launching browser: http://localhost:5234
dotnet watch 🚀 Launched 'http://localhost:5234' with arguments '': process id 12000
info: Microsoft.Hosting.Lifetime[0]
      Application started. Press Ctrl+C to shut down.
info: Microsoft.Hosting.Lifetime[0]
      Hosting environment: Development
info: Microsoft.Hosting.Lifetime[0]
      Content root path: C:\Users\v-yuwzh\blazor11
warn: Microsoft.AspNetCore.HttpsPolicy.HttpsRedirectionMiddleware[3]
      Failed to determine the https port for redirect.
dbug: Microsoft.AspNetCore.Watch.BrowserRefresh.BrowserRefreshMiddleware[1]
      Response markup is scheduled to include browser refresh script injection.
dbug: Microsoft.AspNetCore.Watch.BrowserRefresh.BrowserRefreshMiddleware[2]
      Response markup was updated to include browser refresh script injection.
dbug: Microsoft.AspNetCore.Watch.BrowserRefresh.BrowserScriptMiddleware[0]
      Script injected: /_framework/aspnetcore-browser-refresh.js
dotnet watch 🔥 Hot reload session started.
dotnet watch ⌚ Waiting for changes
dotnet watch 🌐 [Browser #1] Connected to refresh server.
dotnet watch ⌚ [FW] Updated 'C:\Users\v-yuwzh\blazor11\Components\Pages\Home.razor'.
dotnet watch ⌚ File change: Update 'C:\Users\v-yuwzh\blazor11\Components\Pages\Home.razor'.
dotnet watch ⌚ [FW] Updated 'C:\Users\v-yuwzh\blazor11\Components\Pages\Home.razor'.
dotnet watch ⌚ File change: Update 'C:\Users\v-yuwzh\blazor11\Components\Pages\Home.razor'.
dotnet watch ⌚ File updated: .\Components\Pages\Home.razor
dotnet watch 🔥 Hot reload capabilities: AddFieldRva AddInstanceFieldToExistingType AddMethodToExistingType AddStaticFieldToExistingType Baseline ChangeCustomAttributes GenericAddFieldToExistingType GenericAddMethodToExistingType GenericUpdateMethod NewTypeDefinition UpdateParameters.
dotnet watch 🔃 [blazor11 (net10.0)] Updating diagnostics.
dotnet watch 🔥 [blazor11 (net10.0)] Sending update batch #0
dotnet watch 🕵️ [blazor11 (net10.0)] Writing capabilities: Baseline AddMethodToExistingType AddStaticFieldToExistingType AddInstanceFieldToExistingType NewTypeDefinition ChangeCustomAttributes UpdateParameters GenericUpdateMethod GenericAddMethodToExistingType GenericAddFieldToExistingType AddFieldRva
dotnet watch 🕵️ [blazor11 (net10.0)] Applying updates to module f1256bf9-a423-4120-970d-7808bc2c0598.
dotnet watch 🕵️ [blazor11 (net10.0)] Invoking metadata update handlers.
dotnet watch 🕵️ [blazor11 (net10.0)] System.Reflection.Metadata.RuntimeTypeMetadataUpdateHandler.ClearCache
dotnet watch 🕵️ [blazor11 (net10.0)] Microsoft.Extensions.DependencyInjection.ActivatorUtilities+ActivatorUtilitiesUpdateHandler.ClearCache
dotnet watch 🕵️ [blazor11 (net10.0)] System.Text.Json.JsonSerializerOptionsUpdateHandler.ClearCache
dotnet watch 🕵️ [blazor11 (net10.0)] System.ComponentModel.ReflectionCachesUpdateHandler.ClearCache
dotnet watch 🕵️ [blazor11 (net10.0)] Microsoft.AspNetCore.Routing.RouteValueDictionary+MetadataUpdateHandler.ClearCache
dotnet watch 🕵️ [blazor11 (net10.0)] Microsoft.Extensions.Internal.PropertyHelper+MetadataUpdateHandler.ClearCache
dotnet watch 🕵️ [blazor11 (net10.0)] Microsoft.Extensions.Internal.PropertyHelper+MetadataUpdateHandler.ClearCache
dotnet watch 🕵️ [blazor11 (net10.0)] Microsoft.Extensions.Internal.PropertyHelper+MetadataUpdateHandler.ClearCache
dotnet watch 🕵️ [blazor11 (net10.0)] Microsoft.JSInterop.Infrastructure.DotNetDispatcher+MetadataUpdateHandler.ClearCache
dotnet watch 🕵️ [blazor11 (net10.0)] Microsoft.AspNetCore.Components.Routing.RazorComponentsEndpointHttpContextExtensions+MetadataUpdateHandler.ClearCache
dotnet watch 🕵️ [blazor11 (net10.0)] Microsoft.AspNetCore.Components.Endpoints.HotReloadService.ClearCache
dotnet watch 🕵️ [blazor11 (net10.0)] Microsoft.Extensions.Internal.PropertyHelper+MetadataUpdateHandler.ClearCache
dotnet watch 🕵️ [blazor11 (net10.0)] Microsoft.AspNetCore.Components.HotReload.HotReloadManager.UpdateApplication
dotnet watch 🕵️ [blazor11 (net10.0)] Microsoft.AspNetCore.Components.HotReload.HotReloadManager.UpdateApplication
dotnet watch 🕵️ [blazor11 (net10.0)] Microsoft.AspNetCore.Components.Endpoints.HotReloadService.UpdateApplication
dotnet watch 🕵️ [blazor11 (net10.0)] Microsoft.AspNetCore.Components.Endpoints.EndpointComponentState.UpdateApplication
dotnet watch 🕵️ [blazor11 (net10.0)] Microsoft.AspNetCore.Components.HotReload.HotReloadManager.UpdateApplication
dotnet watch 🕵️ [blazor11 (net10.0)] Microsoft.AspNetCore.Components.HotReload.HotReloadManager.UpdateApplication
dotnet watch 🕵️ [blazor11 (net10.0)] Updates applied.
dotnet watch 🔥 [blazor11 (net10.0)] Update batch #0 completed.
dotnet watch 🔥 [blazor11 (net10.0)] Updates applied: 1 out of 1.
dotnet watch 🔥 [blazor11 (net10.0)] Hot reload succeeded.
dotnet watch 🔃 [blazor11 (net10.0)] Refreshing browser.
dotnet watch 🔥 Hot reload change handled in 2557ms.
dbug: Microsoft.AspNetCore.Watch.BrowserRefresh.BrowserRefreshMiddleware[1]
      Response markup is scheduled to include browser refresh script injection.
dbug: Microsoft.AspNetCore.Watch.BrowserRefresh.BrowserRefreshMiddleware[2]
      Response markup was updated to include browser refresh script injection.

EXPECTED
The browser is not stuck, the page is displayed normally.

[javiercn]

@tmat can you take a look?