Do you also have a problem with MCP server, I cannot save like URL of the mcp server from n8n on local host do you know what is the problem? my Save button becomes gray after i put in the URL ?

The save button greys out because VAPI doesn't accept localhost URLs it requires a publicly accessible URL. Your n8n MCP server running on localhost can't be reached by VAPI's servers, so it rejects it before saving. You need to expose your local n8n with a tunnel. Use ngrok or Cloudflare Tunnel to get a public URL pointing to your localhost, then paste that into VAPI instead. Connect with me if you need help setting it up @scaramouche