Error sending message to file:///undefined: TypeError: fetch failed

[vicdotdevelop]

We are running into an issue with our config when starting the MCP server.
Information:

• Selfhosted GitGuardian Instance
• GitHub Copilot in VS Code

log:

2025-09-25 15:24:10.446 [info] Starting server GitGuardianDeveloper
2025-09-25 15:24:10.446 [info] Connection state: Starting
2025-09-25 15:24:10.457 [info] Starting server from LocalProcess extension host
2025-09-25 15:24:10.460 [info] Connection state: Running
2025-09-25 15:24:10.462 [info] Connection state: Error Error sending message to file:///undefined: TypeError: fetch failed

Our setup in .vscode/mcp.json

{
  "servers": {
    "GitGuardianDeveloper": {
      "args": [
        "uvx",
        "--from",
        "git+https://github.com/GitGuardian/gg-mcp.git",
        "developer-mcp-server"
      ],
      "env": {
        "GITGUARDIAN_URL": "https://gitguardian.ourcompanyname.net",
        "GITGUARDIAN_API_KEY": "xxx"
      }
    }
  }
}

Any ideas where the error comes from?