> ## Documentation Index
> Fetch the complete documentation index at: https://crosslink.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Debug mobile reconnection

> Recover a Crosslink mobile app when its desktop host is unavailable

On an HTTPS origin, Crosslink's installed mobile app keeps a small offline shell in the browser cache. If the desktop host stops, the shell opens after a bounded four-second network check, shows **Trying to reconnect**, and retries with backoff instead of exposing a browser connection-error page.

## Try these steps in order

1. Open the Crosslink-powered app on the computer.
2. In the mobile reconnect screen, tap **Attempt reopening the app**.
3. Confirm the phone and computer are on the same Wi-Fi when the host uses **Same network only**.
4. If the host uses **Reachable from anywhere**, confirm that the desktop app reports an active public, tunnel, or relay route.
5. Disable VPNs temporarily on both devices. A VPN can accept a router mapping while silently swallowing the return path.
6. Check the computer's firewall and allow the desktop app to accept incoming connections.

## If Safari shows its own connection error

The offline shell becomes available after the mobile page has loaded successfully once and its service worker has taken control. Open the host once while it is reachable, wait a few seconds, and add the page to the Home Screen. Then test again from the installed app.

<Warning>
  A private-LAN URL such as `http://192.168.1.20` is not a secure browser context. Browsers do not allow that page to install a service worker, so a web app cannot intercept a later navigation after the host is gone. Use an HTTPS tunnel or another HTTPS bootstrap origin when the cached reconnect screen is a requirement.
</Warning>

Safari may also remove site data under storage pressure or after the user clears website data. In that case the browser no longer has a cached shell to display; open a fresh pairing QR from the desktop host to install it again.

## Collect diagnostics

On the desktop host, note:

* the selected connection mode;
* the routes listed in the pairing settings;
* whether the host process is still running;
* any `CL-P…` code shown in the pairing card;
* the host's structured Crosslink logs around the failed attempt.

For SDK integrations, log client state transitions and the host connectivity snapshot. See [Reconnection](/connections/reconnection) and [Troubleshooting](/resources/troubleshooting) for the relevant APIs and error categories.

## Prevent the host from disappearing

In packaged desktop apps that support it, open the settings cog and enable **Start at login and keep Crosslink running**. Closing the window then leaves the host active in the background, and the operating system starts it again after login.