Failed to connect to streaming HTTP MCP server HTTPS endpoint

[khteh]

ASP.Net Core 10 kestrel server:

    "Kestrel": {
        "EndpointDefaults": {
            "Protocols": "Http1AndHttp2AndHttp3"
        },
        "Endpoints": {
            "Https": {
                "Url": "https://*",
                "Protocols": "Http1AndHttp2AndHttp3",
                "Certificate": {
                    "Path": "/tmp/localhost.pfx",
                    "Password": "AspNetCoreWebApi"
                }
            }
        },
        "Certificates": {
            "Default": {
                "Path": "/tmp/localhost.pfx",
                "Password": "AspNetCoreWebApi"
            }
        }
    },

MCP endpoint mapped at app.MapMcp("/mcp");. Deployed and run the app successfully in a local k8s cluster. VS Code ./vscode/mcp.json:

{
  "servers": {
    "aspnetcorewebapi": {
      "type": "http",
      "url" : "https://10.152.183.134/mcp"
    }
  },
  "sandbox": {
    "filesystem": {
      "allowWrite": ["${workspaceFolder}"]
    },
    "network": {
      "allowedDomains": ["api.example.com"]
    }
  }
}

Starting the aspnetcorewebapi server in Extensions view hit the following error:

2026-08-02 16:55:16.463 [info] Connection state: Error Error sending message to https://10.152.183.134/mcp: TypeError: fetch failed: self signed certificate; if the root CA is installed locally, try running Node.js with --use-system-ca

The usual MVC part of the app works. Why does the error message even suggest Node.JS!?!