How to setup a remote MCP server hosted locally in cursor?

How To
1

Problem:
I created a MCP server with SSE transport and hosted it using fastAPI in my virtual network (adding below the implementation). I was able to access this server through a browser in my network, but when I tried setting it up in cursor, it is failing with the below error:

2025-04-17 19:05:08.389 [error] -DPA: Client error for command SSE error: TypeError: fetch failed: unable to verify the first certificate

Did anyone see this error? If so, how did you fix it?

Implementation details:

  1. mcp_server with a simple tool:

from mcp.server.fastmcp import FastMCP

mcp = FastMCP(“name”)

@mcp.tool()
def some_tool(question: str) → str:
return “Hello, world!”

if name == “main”:
mcp.run(transport=“stdio”)

  1. Hosted it using fastAPI:

…
sse = SseServerTransport(“/messages/”)
app.router.routes.append(Mount(“/messages”, app=sse.handle_post_message))

@app.get("/sse", tags=["MCP"])
async def handle_sse(request: Request):
    """Handle SSE connections for MCP server."""
    try:
        # Log request details
        logger.info(f"New SSE connection from {request.client.host}")
        logger.info(f"Request headers: {dict(request.headers)}")

        async with sse.connect_sse(request.scope, request.receive, request._send) as (
            read_stream,
            write_stream,
        ):
            init_options = mcp._mcp_server.create_initialization_options()
            await mcp._mcp_server.run(
                read_stream,
                write_stream,
                init_options
            )
    except Exception as e:
        logger.error(f"Error in MCP SSE handler: {str(e)}")
        logger.error(f"Traceback: {traceback.format_exc()}")
        return JSONResponse(
            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
            content={"error": "Internal server error"},
        )

…

  1. When I tried accessing the endpoint through a terminal or a web browser, it is responding correctly (accessing SSE endpoint is returning the /messages endpoint)
    For e.g., something like:

event: endpoint
data: /messages/?session_id=749358774849032423

  1. But when I tried to set this up in cursor using the below config, it is continuously failing with the above error:

{
“mcpServers”: {
“name”: {
“url”: “https://url/sse”
}
}
}