Error “Could not connect to your MCP server” when integrating external tool via SSE in AI Agent

Questions
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Hey guys, this is a known issue.
It turns out MCP uses SSE connection and that’s a new thing for n8n.

So you have to adapt the infrastructure to treat the connection differently when using MCP.

With Coolify I found out you have to disable gzip compression for the /mcp path, while leaving it enabled for everything else.

That’s also true for traefik and nginx users.

Here’s some useful resources:

The video is in Portuguese, but it’s very well explained. Enable subtitles.

@Robin_Ramkhalawan @Lucas_Mozzatto_Chave @damiao_j @Jonathan_Politzki @khai-mle

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