When you sign in to Zapier MCP through your browser, the sign-in window may complete successfully but your AI client never receives the result. This typically happens with terminal-based AI clients, certain WSL configurations, or browser extensions that interfere with sign-in redirects.
Symptom
The sign-in window opens in your browser and appears to finish successfully, but your AI client never receives the result and the connection does not complete.
Causes
- Claude Code is running on WSL (Windows Subsystem for Linux) and the sign-in redirect cannot reach the client.
- VS Code extensions are interfering with the sign-in process.
- A terminal-based AI client cannot receive the sign-in result back from the browser.
- An older version of Cursor or Windsurf has a known sign-in bug that prevents the connection from completing.
- Claude Desktop did not pick up the completed sign-in.
How to fix it
Try one or more of the following:
- Start the sign-in from inside your AI client and wait for it to prompt you to open your browser.
- Do not open the sign-in link before your AI client is ready to receive the result.
- Check that your browser is not blocking pop-ups or redirects from
zapier.com. - Update your AI client to the latest version.
- Use a different browser. Some browser extensions can interfere with sign-in redirects.
- Restart your AI client (especially Claude Desktop) and try connecting again.
- If you are using WSL, run your AI client from a native Windows terminal instead.
- If you are using VS Code with extensions installed, disable them and try connecting again.
- If your AI client supports it, rotate your server URL and set up the connection again from scratch.
Still need help?
If this article did not fix the issue:
- Ask in the Zapier Community for advice from experienced Zapier users.
- Contact the Zapier MCP team for feedback or help.
- Learn more about getting help and support with Zapier.