Hey, not sure if anyone else has issues with the n8n-mcp server?
Describe the problem/error/question
The n8n MCP (Model Context Protocol) consistently fails authentication with “Failed to authenticate with n8n. Please check your API key” error, despite direct curl requests working perfectly with the same API key and configuration. This prevents programmatic workflow management through Claude Desktop.
What is the error message (if any)?
{
"success": false,
"error": "Failed to authenticate with n8n. Please check your API key.",
"code": "AUTHENTICATION*\_ERROR"*
}
Please share your workflow
The issue occurs when trying to list or create workflows programmatically.
Direct API testing works:
curl -s -H "X-N8N-API-KEY: [token]" http://localhost:5678/api/v1/workflows?limit=1
# Returns workflow data successfully
Share the output returned by the last node
N/A - This is an API authentication issue, not a workflow execution issue.
Information on your n8n setup
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n8n version: 1.113.3
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Database (default: SQLite): SQLite (default)
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n8n EXECUTIONS_PROCESS setting (default: own, main): own (default)
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Running n8n via (Docker, npm, n8n cloud, desktop app): npm (global install)
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Operating system: macOS (Darwin 25.0.0)
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n8n version:
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Database:
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n8n EXECUTIONS_PROCESS setting:
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Running n8n via:
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Operating system:
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n8n MCP version: 2.13.2
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Multiple MCP processes cause conflicts
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Direct API calls work, MCP wrapper fails
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Issue is intermittent - worked earlier today but fails consistently now
Additional Context:
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n8n MCP version: 2.13.2
-
Multiple MCP processes cause conflicts
-
Direct API calls work, MCP wrapper fails
-
Issue is intermittent - worked earlier today but fails consistently now
-