MCP server Claude

Running n8n in docker behind a proxy manager (docker too) I have configured a mcp local in Claude and it works but when I try to connect with n8n if fails.

What is wrong here?

To integrate Claude via MCP, n8n requires a dedicated server node configured with an official API key and a network connection capable of accessing anthropic.com.

From the Claude it works already. The issue is that from the MCP client it can see the MCP server

Any idea? I still fails