---
title: "Has Agent Crashed?"
description: "How to fix connection issues when the BrowserOS agent is not responding"
---

If you see **"Failed to Fetch"** or **"Unable to connect to BrowserOS agent"**, your agent has been killed.

<Frame>
  <img src="/images/troubleshooting/failed-to-fetch-error.png" alt="Failed to fetch error" />
</Frame>

## Windows: Did you allow the BrowserOS Agent?

When BrowserOS starts for the first time on Windows, a popup will ask if you want to allow **BrowserOS Agent** to access the network. Click **Allow** — the agent runs as a separate process alongside the browser and needs this permission to work. If you clicked **Cancel** or missed this prompt, the agent won't be able to connect.

<Frame>
  <img src="/images/windows-installation/windows-installation-allow-browseros-agent.png" alt="Allow BrowserOS Agent network access prompt" />
</Frame>

To fix this, go to **Windows Security → Allow an app through your network settings**, and make sure **BrowserOS Agent** is enabled.

## Fix It

<Steps>
  <Step title="Go to Settings → MCP Server and click Restart">
    Open **Settings** from the sidebar, scroll to the MCP Server section, and click **Restart**. Wait a couple of minutes.

    <Frame>
      <img src="/images/troubleshooting/mcp-server-restart.png" alt="Click Restart in MCP Server Settings" />
    </Frame>
  </Step>

  <Step title="If restart doesn't work, restart the BrowserOS Agent manually">
    <Tabs>
      <Tab title="Windows">
        1. Open **Task Manager** — press `Ctrl + Shift + Esc` or right-click the taskbar and select **Task Manager**.
        2. In the search bar at the top, type **browseros agent**.
        3. Right-click **BrowserOS Agent** and select **End task**.
        4. Reopen **BrowserOS** — the agent will restart automatically.

        <Frame>
          <img src="/images/windows-installation/troubleshoot-search-restart-agent-task-manager.png" alt="Search for BrowserOS Agent in Task Manager and restart it" />
        </Frame>

        <Note>If the agent still doesn't reconnect, end both **BrowserOS** and **BrowserOS Agent** in Task Manager, then reopen the app.</Note>
      </Tab>
      <Tab title="macOS">
        Right-click BrowserOS in the Dock → **Quit**, then reopen the app.
      </Tab>
    </Tabs>
  </Step>
</Steps>

## Still Not Working?

<AccordionGroup>
  <Accordion title="Check if another application is using the port">
    The agent runs on port `9100` by default. If another application is using this port, BrowserOS cannot start the agent.

    <Tabs>
      <Tab title="macOS/Linux">
        Find the process:
        ```bash
        lsof -i :9100
        ```

        Kill it (replace `PID` with the process ID from above):
        ```bash
        kill -9 PID
        ```
      </Tab>
      <Tab title="Windows">
        Find the process:
        ```powershell
        netstat -ano | findstr :9100
        ```

        Kill it (replace `PID` with the process ID from above):
        ```powershell
        taskkill /PID PID /F
        ```
      </Tab>
    </Tabs>

    Then restart BrowserOS.
  </Accordion>

  <Accordion title="Check your firewall or antivirus settings">
    Some firewalls may block local connections. Make sure your firewall allows connections to `127.0.0.1:9100`.

    **Windows users:** Antivirus software sometimes triggers a false positive. Try temporarily disabling your antivirus and restarting BrowserOS.
  </Accordion>
</AccordionGroup>

## Get Help

If you're still experiencing issues, reach out:

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    Get help from the community
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    Join our Slack
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