The httpx.ConnectError usually indicates a network connectivity issue rather than authentication. Since you enabled private connectivity, your MCP server is likely only accessible within the VPC or through a configured private endpoint. From a local notebook or environment outside that network, the connection will fail. To fix this, either:

• Use a notebook or compute instance within the same VPC or subnet.
• Configure a secure VPN or bastion host to access the private endpoint.
• If public access is acceptable, adjust the MCP deployment to allow public connectivity temporarily for testing.
  Check the MCP docs on private connectivity and endpoints — the error is consistent with trying to reach a private-only service from outside its network.”

I can also draft a simpler, one-paragraph version for quick forum posting if you want.