Skip to main content

Claude Desktop Remote MCP Connection Issues

When connecting Claude Desktop to the Atlan Remote MCP server, OAuth login may fail because of network restrictions on the local callback. This page covers the most common issues and how to fix them.

localhost refused to connect during OAuth login​

Error

localhost refused to connect — the local OAuth callback listener couldn't be reached.

Cause​

Claude Desktop temporarily opens a local listener (port 7110, chosen at runtime) to receive the OAuth response from Atlan. If anything blocks the redirect to localhost before Claude Desktop captures it, the login fails. Common causes:

  • Claude Desktop was closed or backgrounded before the redirect arrived.
  • The OAuth window timed out (approximately 5 minutes).
  • A VPN, corporate proxy, or antivirus product intercepted the localhost loopback.
  • Another process was already holding the port.

Solution​

  1. Fully quit Claude Desktop. Wait approximately 5 minutes, then reopen it and re-initiate the Atlan connection. Complete the login without closing the browser tab until Atlan tools appear in Claude Desktop.
  2. If you're on a VPN or corporate proxy, disable it just for the login step—localhost loopback traffic can be intercepted by network security tools.
  3. Inspect the MCP server logs (see Log file locations below) to confirm the exact failure mode.
info

If your environment can't reliably permit localhost callbacks—for example, on locked-down corporate devices—use Claude Connector instead. It authenticates through the browser without a local OAuth callback.

Log file locations​

If you need to inspect MCP server logs to diagnose connection issues, the log files are at:

  • macOS: ~/Library/Logs/Claude/mcp-server-atlan*.log
  • Windows: %APPDATA%\Claude\logs\mcp-server-atlan*.log
  • Linux: ~/.config/Claude/logs/mcp-server-atlan*.log

See also​

Need help​

If you need assistance after trying these steps, contact Atlan Support.