Cannot debug Blazor Wasm application on .Net 6: Unable to attach to browser

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

When launching a Blazor wasm application in debug, the browser (either Chrome or Edge) tab will open and the application will crash with “got exception System.Net.WebSockets.WebSocketException (0x80004005): The server returned status code ‘500’ when status code ‘101’ was expected.”

By setting "launchBrowser": false, I can open a Chrome tab to the application but the debugging still doesn’t work.

If I use Shift-Alt-D, I get a page that says Unable to find debuggable browser tab. Could not get a list of browser tabs from http://localhost:9222/json. Ensure your browser is running with debugging enabled.. I can however navigate to http://localhost:9222/json and see the document.

This is very similar to https://github.com/dotnet/aspnetcore/issues/26824 but the fix does not work for me.

I have uninstalled every other .Net sdk version and have tried with my proxy disabled.

This happens with every Blazor Wasm app I can launch including the default project template.

This issue does not happen with Firefox but it shows a message that debugging is explicitly not supported

Expected Behavior

The application should open in the browser all allow breakpoints to be set in the code.

Steps To Reproduce

• Install .Net 6
• Create a new project with dotnet new blazorwasm
• Open the project in Visual Studio 2022
• Launch the application either with IIS or Kestrel targetting Chrome or Edge

Exceptions (if any)

got exception System.Net.WebSockets.WebSocketException (0x80004005): The server returned status code ‘500’ when status code ‘101’ was expected. at System.Net.WebSockets.WebSocketHandle.ConnectAsync(Uri uri, CancellationToken cancellationToken, ClientWebSocketOptions options) at System.Net.WebSockets.ClientWebSocket.ConnectAsyncCore(Uri uri, CancellationToken cancellationToken) at Microsoft.WebAssembly.Diagnostics.DevToolsProxy.Run(Uri browserUri, WebSocket ideSocket) at Microsoft.WebAssembly.Diagnostics.DebugExtensions.<>c__DisplayClass2_0.<<UseDebugProxy>g__ConnectProxy|5>d.MoveNext()

.NET Version

6.0.202

Anything else?

I’m using Visual Studio Professional 2022 v17.1.6 Using Chrome Version 101.0.4951.41 (Official Build) (64-bit) Using Edge Version 100.0.1185.50 (Official build) (64-bit)

dotnet --info output:

F:\temp>dotnet --info .NET SDK (reflecting any global.json): Version: 6.0.202 Commit: f8a55617d2

Runtime Environment: OS Name: Windows OS Version: 10.0.19042 OS Platform: Windows RID: win10-x64 Base Path: C:\Program Files\dotnet\sdk\6.0.202\

Host (useful for support): Version: 6.0.4 Commit: be98e88c76

.NET SDKs installed: 6.0.202 [C:\Program Files\dotnet\sdk]

.NET runtimes installed: Microsoft.AspNetCore.App 6.0.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App] Microsoft.NETCore.App 6.0.0-rc.2.21480.5 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.NETCore.App 6.0.4 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] Microsoft.WindowsDesktop.App 6.0.4 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

What Chrome shows before crashing:

The debug tab:

Log in visualstudio-js-debugger.txt:

{"tag":"runtime.launch","timestamp":1651256875766,"message":"Launch returned error","metadata":{"error":{"message":"Unable to attach to browser","stack":"Error: Unable to attach to browser\n at h.target [as prepareLaunch] (c:\\program files\\microsoft visual studio\\2022\\professional\\common7\\ide\\commonextensions\\microsoft\\jsdiagnostics\\debugger\\debugAdapter\\out\\src\\targets\\browser\\browserLauncher.js:124:19)\n at h.result (c:\\program files\\microsoft visual studio\\2022\\professional\\common7\\ide\\commonextensions\\microsoft\\jsdiagnostics\\debugger\\debugAdapter\\out\\src\\targets\\browser\\browserLauncher.js:168:15)\n at t.Binder.captureLaunch (c:\\program files\\microsoft visual studio\\2022\\professional\\common7\\ide\\commonextensions\\microsoft\\jsdiagnostics\\debugger\\debugAdapter\\out\\src\\binder.js:248:13)\n at t.Binder._launch (c:\\program files\\microsoft visual studio\\2022\\professional\\common7\\ide\\commonextensions\\microsoft\\jsdiagnostics\\debugger\\debugAdapter\\out\\src\\binder.js:224:9)\n at async Promise.all (index 5)\n at t.Binder.result [as _boot] (c:\\program files\\microsoft visual studio\\2022\\professional\\common7\\ide\\commonextensions\\microsoft\\jsdiagnostics\\debugger\\debugAdapter\\out\\src\\binder.js:172:9)\n at t.default._onMessage (c:\\program files\\microsoft visual studio\\2022\\professional\\common7\\ide\\commonextensions\\microsoft\\jsdiagnostics\\debugger\\debugAdapter\\out\\src\\dap\\connection.js:145:27)"},"wasCancelled":false,"name":"h"},"level":2}

[Hastaroth1]

Thank you for the very fast response.

Here is the full content of http://localhost:9222/json:

[ {
   "description": "",
   "devtoolsFrontendUrl": "/devtools/inspector.html?ws=localhost:9222/devtools/page/CD8A6D3F7258E91BE133FED64B0054BD",
   "id": "CD8A6D3F7258E91BE133FED64B0054BD",
   "title": "New Tab",
   "type": "page",
   "url": "http://localhost:9222/json",
   "webSocketDebuggerUrl": "ws://localhost:9222/devtools/page/CD8A6D3F7258E91BE133FED64B0054BD"
}, {
   "description": "",
   "devtoolsFrontendUrl": "/devtools/inspector.html?ws=localhost:9222/devtools/page/5763436CF7381E8A8A19CFE2601472F9",
   "id": "5763436CF7381E8A8A19CFE2601472F9",
   "parentId": "CD8A6D3F7258E91BE133FED64B0054BD",
   "title": "chrome-untrusted://new-tab-page/one-google-bar?paramsencoded=",
   "type": "iframe",
   "url": "chrome-untrusted://new-tab-page/one-google-bar?paramsencoded=",
   "webSocketDebuggerUrl": "ws://localhost:9222/devtools/page/5763436CF7381E8A8A19CFE2601472F9"
}, {
   "description": "",
   "devtoolsFrontendUrl": "/devtools/inspector.html?ws=localhost:9222/devtools/page/D0A51793D1CEEA13D243659C7F0711A9",
   "id": "D0A51793D1CEEA13D243659C7F0711A9",
   "parentId": "5763436CF7381E8A8A19CFE2601472F9",
   "title": "https://ogs.google.com/u/0/widget/app?origin=chrome-untrusted%3A%2F%2Fnew-tab-page&origin=chrome%3A%2F%2Fnew-tab-page&cn=app&pid=1&spid=243&hl=en",
   "type": "iframe",
   "url": "https://ogs.google.com/u/0/widget/app?origin=chrome-untrusted%3A%2F%2Fnew-tab-page&origin=chrome%3A%2F%2Fnew-tab-page&cn=app&pid=1&spid=243&hl=en",
   "webSocketDebuggerUrl": "ws://localhost:9222/devtools/page/D0A51793D1CEEA13D243659C7F0711A9"
}, {
   "description": "",
   "devtoolsFrontendUrl": "/devtools/inspector.html?ws=localhost:9222/devtools/page/103DEB7223115B727C90F47CBFB925E6",
   "faviconUrl": "https://c.s-microsoft.com/favicon.ico?v2",
   "id": "103DEB7223115B727C90F47CBFB925E6",
   "title": "Microsoft – Nuage, ordinateurs, Applications et jeux",
   "type": "page",
   "url": "https://www.microsoft.com/fr-ca/",
   "webSocketDebuggerUrl": "ws://localhost:9222/devtools/page/103DEB7223115B727C90F47CBFB925E6"
}, {
   "description": "",
   "devtoolsFrontendUrl": "/devtools/inspector.html?ws=localhost:9222/devtools/page/F440302FC1485F93B2317B45C6D40685",
   "id": "F440302FC1485F93B2317B45C6D40685",
   "title": "Privacy Badger",
   "type": "background_page",
   "url": "chrome-extension://pkehgijcmpdhfbdbbnkijodmdjhbjlgp/_generated_background_page.html",
   "webSocketDebuggerUrl": "ws://localhost:9222/devtools/page/F440302FC1485F93B2317B45C6D40685"
}, {
   "description": "",
   "devtoolsFrontendUrl": "/devtools/inspector.html?ws=localhost:9222/devtools/page/7292BDC81AC43392BF5FBBE13E47EDD5",
   "id": "7292BDC81AC43392BF5FBBE13E47EDD5",
   "title": "Square",
   "type": "background_page",
   "url": "chrome-extension://nadebckkcfbjaddfpcklodnmokipjlli/_generated_background_page.html",
   "webSocketDebuggerUrl": "ws://localhost:9222/devtools/page/7292BDC81AC43392BF5FBBE13E47EDD5"
}, {
   "description": "",
   "devtoolsFrontendUrl": "/devtools/inspector.html?ws=localhost:9222/devtools/page/92B2C67BAFA4A554BC73ADA379150CA5",
   "id": "92B2C67BAFA4A554BC73ADA379150CA5",
   "title": "uBlock Origin",
   "type": "background_page",
   "url": "chrome-extension://cjpalhdlnbpafiamejdnhcphjbkeiagm/background.html",
   "webSocketDebuggerUrl": "ws://localhost:9222/devtools/page/92B2C67BAFA4A554BC73ADA379150CA5"
} ]

Here is the full debugger file

visualstudio-js-debugger.txt

[xperiandri]

Works for me on 7.0 RTM There were some issue occasionally but cleaning the solution helped. Have you solved your issue guys?