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Fix: lemlist MCP Server Not Connecting in Claude Desktop

If you've configured the lemlist MCP server in Claude Desktop but it's showing an error message like "MCP lemlist: Server disconnected", this guide explains how to fix it.

Prerequisites

Before troubleshooting, confirm you've already:

  1. Opened your Claude Desktop configuration file (claude_desktop_config.json)

  2. Added the lemlist MCP server configuration with the mcp-remote command

If you haven't done this yet, see: How to configure the lemlist MCP server in Claude Desktop

Symptoms

You may see one or more of these issues:

  • Error message: "MCP lemlist: Server disconnected. For troubleshooting guidance, please visit our debugging documentation"

    [Screenshot: Claude Desktop showing yellow warning banner "MCP lemlist: Server disconnected"]

  • Claude Desktop shows a warning banner with "Open developer settings" button

  • The lemlist connector is not appearing in Claude Desktop's context panel

  • Terminal shows: command not found: node or command not found: npm

  • Terminal shows permission errors: npm error code EACCES or permission denied

Root Causes

The lemlist MCP integration requires three components to work together:

  1. Node.js and npm — Runtime environment that executes the MCP server

  2. mcp-remote package — Tool that handles OAuth and connects to lemlist's servers

  3. Proper permissions — Write access to install global npm packages

If any of these is missing or misconfigured, the connection fails.

Solution

Follow these steps in order. Most users will fix the issue at Step 1.

Step 1: Install Node.js (Most Common Fix)

If you see command not found: node in Terminal, Node.js is not installed.

Install Node.js:

  1. Go to https://nodejs.org

  2. Click the large green LTS button (Long Term Support version)

  3. Open your Downloads folder and double-click the .pkg file (e.g., node-v24.17.0.pkg)

  4. Follow the installer prompts:

    • Click Continue

    • Accept the license agreement

    • Click Install

    • Enter your Mac password when prompted

    • Wait for installation to complete

Verify Installation:

  1. Open Terminal (Cmd + Spacebar → type "terminal" → press Enter)

  2. Type: node --version

  3. Press Enter

Expected result: You should see a version number like v24.17.0

If you see the version number, proceed to Step 2.

Step 2: Install mcp-remote

Once Node.js is confirmed installed, you can install the mcp-remote package.

Install mcp-remote:

  1. In Terminal, type: sudo npm install -g mcp-remote

  2. Press Enter

  3. Enter your Mac password when prompted (you won't see it while typing — this is normal)

  4. Wait for installation to complete

Expected result: You should see added 81 packages in 958ms or similar.

Permission Error? If you see npm error code EACCES or permission denied, the sudo command in Step 2 fixes this. The sudo flag gives the installer administrator permissions.

Step 3: Restart Claude Desktop

After mcp-remote is installed, you must restart Claude Desktop for the changes to take effect.

  1. Quit Claude Desktop completely (Cmd + Q)

  2. Reopen Claude Desktop

Verify Connection:

  1. Look for the lemlist authorization screen — this means the connection is working

  2. Select your lemlist team from the dropdown

  3. Click Authorize

  4. The authorization window will close automatically

Once authorized, you should see:

  • The lemlist connector listed in Claude Desktop's Context panel

  • No error messages in the interface

  • Available lemlist tools like get_campaigns and get_campaigns_stats

Common Issues and Fixes

"Command not found: node" even after installing Node.js

Cause: Terminal cache hasn't refreshed after installation.

Fix:

  1. Close Terminal completely (Cmd + Q)

  2. Reopen Terminal

  3. Try node --version again

If still not found, restart your Mac:

  1. Apple menu → Restart

  2. Open Terminal and try again

Permission errors: "EACCES" or "permission denied"

Cause: npm doesn't have permission to write to the global packages directory.

Fix: Always use sudo when installing global npm packages:

sudo npm install -g mcp-remote

The sudo command temporarily gives you administrator permissions for that command only.

OAuth authorization window doesn't appear

Cause: The MCP connection isn't established yet.

Fixes:

  1. Verify all steps above are complete

  2. Check that you used sudo npm install -g mcp-remote (not just npm install)

  3. Try restarting Claude Desktop again

  4. If lemlist still doesn't authorize, check the developer settings for detailed error logs

To open developer settings:

  1. In Claude Desktop, look for any warning banner related to lemlist

  2. Click "Open developer settings"

  3. Scroll through the logs for error messages that start with "lemlist"

Installation appears to hang or freeze

Cause: Large package downloads can take time, especially on slower connections.

Fix:

  1. Do not close Terminal or restart your Mac

  2. Wait at least 5 minutes before assuming it's frozen

  3. If you must stop it, press Ctrl + C to cancel, then try again

Prevention: Best Practices

  • Always use sudo for global npm installs — This prevents permission issues from occurring

  • Keep Node.js updated — Run sudo npm install -g npm every few months to get the latest npm version

  • Restart Claude Desktop after any system changes — MCP connections are established when Claude Desktop starts

Still Having Issues?

If you've completed all steps and the lemlist MCP connection still isn't working:

  1. Check the lemlist authorization status in Claude Desktop (see Verify Connection above)

  2. Try force-quitting Claude Desktop and reopening it

  3. If you see specific error messages, search our Help Center for that error text

  4. Contact lemlist support with a screenshot of the error message and the output from your Terminal installation steps

Related Articles
Set up the lemlist MCP server in your LLM client (OAuth or API key)
How to use the lemlist MCP from Claude or ChatGPT
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