Cannot conect to stateless streamable http mcp server developed using C# SDK using VSCode mcp client

[ananthubabu-geodis]

Developed and deployed a mcp server exposing majorly prompts and just one tool for testing and is getting the error :

2025-06-20 14:50:02.632 [info] Starting server from LocalProcess extension host
2025-06-20 14:50:02.663 [info] Connection state: Running
2025-06-20 14:50:03.942 [info] Discovered 0 tools
2025-06-20 14:50:04.775 [info] Connection state: Error ; will retry with new session ID

I have provided the options

            .ConfigureServices((_, services) =>
                {
                    services
                        .AddMcpServer(options =>
                        {
                            options.ServerInfo = new Implementation
                            {
                                Name = "Vite MCP Server",
                                Version = "1.0.0"
                            };
                        })
                        .WithHttpTransport(options =>
                        {
                            options.IdleTimeout = TimeSpan.FromMinutes(15);
                            options.MaxIdleSessionCount = 100;
                            options.Stateless = true;
                        })
                        .WithToolsFromAssembly()
                        .WithPromptsFromAssembly();
                });

also in Startup.cs :

            app.UseCors("CorsPolicy");
            app.UseEndpoints(endpoints =>
            {
                endpoints.MapMcp("/mcp");
            });

It works fine in local machine using http ports but not in https.

The hosted server also returns the error.

Could this be because of any certificate issue?

VSCode is my mcp client.

[ananthubabu-geodis]

I am getting a certificate issue in mcp inspector

Error from MCP server: TypeError: fetch failed
    at node:internal/deps/undici/undici:13502:13
    at process.processTicksAndRejections (node:internal/process/task_queues:105:5)
    at async StreamableHTTPClientTransport.send (file:///C:/Users/ananthu.babu/AppData/Local/npm-cache/_npx/5a9d879542beca3a/node_modules/@modelcontextprotocol/sdk/dist/esm/client/streamableHttp.js:251:30) {
  [cause]: Error: unable to get local issuer certificate
      at TLSSocket.onConnectSecure (node:_tls_wrap:1679:34)
      at TLSSocket.emit (node:events:518:28)
      at TLSSocket._finishInit (node:_tls_wrap:1078:8)
      at ssl.onhandshakedone (node:_tls_wrap:864:12) {
    code: 'UNABLE_TO_GET_ISSUER_CERT_LOCALLY'
  }
}

VSCode is my mcp client.

Any idea how to solve this?

[connor4312]

You will want to make sure your certificate is trusted by your machine's certificate authorities.