MCP

Connected account not found error

This error occurs when MCP cannot find a valid connected account for authentication:

• Specify an account: Provide either connected_account_id or user_id in your MCP configuration
• Default behavior: Without specification, MCP uses user_id=default. If multiple connections exist with the same user_id, the most recent is used
• Verification checklist:
  • Account status is ACTIVE (not deleted)
  • Account belongs to the same auth config used to create the MCP server

Learn more: Single Toolkit MCP

Getting 404 errors

Verify your URL format matches one of these patterns:

• https://mcp.composio.dev/composio/server/<UUID>/mcp
• https://apollo-<randomID>-composio.vercel.app/v3/mcp/<UUID>
• https://apollo.composio.dev/v3/mcp/<UUID>

Testing and debugging

If experiencing issues, test your MCP server with:

• Postman MCP Requests
• MCP Inspector

This helps identify whether the issue is with your MCP client or the server.

Reporting MCP issues

When reporting to support, provide:

• Error message: Complete error details

• MCP server URL: The exact URL you're connecting to and the corresponding mcp_server_id

  

• Testing results: Whether issue reproduces in MCP Inspector/Postman or only in specific client

• Connected account ID: If facing connection issues

  

• Reproduction steps: Clear steps to reproduce the issue

Getting help

• Email: support@composio.dev
• Discord: #support-form