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# Sign-in completes in browser but MCP client does not connect

> Troubleshoot OAuth sign-in flows that complete in the browser but fail to connect your MCP client to Zapier MCP.

This article covers OAuth sign-in issues that affect listed MCP clients such as Claude, ChatGPT, Cursor, Grok Bot, and VS Code. If you are using an unlisted MCP client with a connection token, you do not use the browser sign-in flow. Go to the [Unlisted MCP client tab](#how-to-fix-it) instead.

When you sign in to Zapier MCP through your browser, the sign-in window may complete successfully but your MCP client never receives the result. This typically happens with terminal-based MCP 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 MCP 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 MCP client.
* VS Code extensions are interfering with the sign-in process.
* A terminal-based MCP 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

<AccordionGroup>
  <Accordion title="General fixes">
    Try one or more of the following:

    * Start the sign-in from inside your MCP client and wait for it to prompt you to open your browser.
    * Do not open the sign-in link before your MCP client is ready to receive the result.
    * Check that your browser is not blocking pop-ups or redirects from `zapier.com`.
    * Update your MCP client to the latest version.
    * Use a different browser. Some browser extensions can interfere with sign-in redirects.
    * Restart your MCP client (especially Claude Desktop) and try connecting again.
  </Accordion>

  <Accordion title="Claude Code on WSL">
    OAuth redirects cannot reach Claude Code when it is running inside WSL. Run your MCP client from a native Windows terminal instead of a WSL terminal, then try connecting again.
  </Accordion>

  <Accordion title="VS Code with extensions">
    Extensions can intercept the OAuth redirect before VS Code receives it. Disable your extensions and try connecting again. If the connection succeeds, re-enable extensions one at a time to identify the conflict.
  </Accordion>

  <Accordion title="Unlisted MCP client (connection token)">
    If your MCP client does not support OAuth, [regenerate your connection token](/mcp/get-started/connect/other#regenerate-a-token) and set up the connection again from scratch using the new server URL.
  </Accordion>
</AccordionGroup>

## Still need help?

* [Ask in the Zapier Community](https://community.zapier.com/) for advice from experienced Zapier users.
* [Contact the Zapier MCP team](https://mcp.zapier.app/home) for feedback or help.