> For the complete documentation index, see [llms.txt](https://docs.drizz.dev/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.drizz.dev/desktop-app/networks-and-preflight.md).

# Networks, proxies & preflight

Preflight reports whether the desktop app can reach every service it needs, and names the layer that fails.

{% hint style="info" %}
`Help` → **Network Preflight**
{% endhint %}

|                        |                                                                                                                       |
| ---------------------- | --------------------------------------------------------------------------------------------------------------------- |
| **Platforms**          | macOS                                                                                                                 |
| **When it runs**       | Automatically before device setup, and any time you ask for it                                                        |
| **What "ready" means** | Every check shows **OK** and the connection status reads **Ready**                                                    |
| **Corporate TLS**      | Drizz reads the macOS system certificate store — no configuration needed when the root certificate is installed there |
| **Watch out**          | Works on a hotspot but not on office wifi means TLS inspection or an egress rule, not a Drizz fault                   |

## Prerequisites

* Drizz desktop app installed
* A network connection
* For corporate networks: the company root certificate in the macOS **system** keychain

## Run preflight

1. Open **Help → Network Preflight**.
2. Click **Run**. Drizz also runs this check automatically before desktop setup.
3. Read the **connection status** at the top.
4. Identify the rows that are not **OK**. Preflight names the specific service or network layer that failed.
5. Fix the topmost failing row. A failure high in the list explains the failures below it.
6. Click **Run** to re-execute the check.
7. Confirm every check shows **OK** and the status reads **Ready**, then click **Continue**.

## What it checks

Four layers, in the order they matter.

| Layer                 | What's being confirmed                                                            |
| --------------------- | --------------------------------------------------------------------------------- |
| **Network integrity** | DNS resolution, proxy routing, HTTPS reachability                                 |
| **Sign-in**           | That the identity services behind sign-in are reachable and your session is valid |
| **Platform services** | That the services which allocate devices and store your tests respond             |
| **Live connection**   | That the real-time channel used to stream device state and logs stays open        |

## Corporate networks, proxies and TLS inspection

Drizz reads the **macOS system certificate store**. On a network with a TLS-inspecting proxy, no configuration is required when the company root certificate is installed in the system keychain.

| Symptom                                               | Diagnosis                                                                                                                                                                 |
| ----------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Works on a phone hotspot, fails on the office network | **Cause:** TLS inspection or an egress rule. **Fix:** run preflight on both networks and compare which rows differ. That list goes to IT                                  |
| Preflight fails only on the corporate network         | **Cause:** the corporate root certificate is not in the macOS system keychain. **Fix:** install it in the system keychain, not a user keychain or a browser store         |
| Runs start and then die partway                       | **Cause:** a proxy terminating long-lived connections after a fixed idle period. **Fix:** exempt the real-time connection from the idle timeout                           |
| An automatic app update can't download                | **Cause:** the same egress rules that block sign-in. **Fix:** run preflight before treating the update as broken. See [Updates & forced updates](/desktop-app/updates.md) |

Checks to raise with IT when preflight fails on a corporate network:

* Is the corporate root certificate installed in the **system** keychain, not just a user keychain or a browser store?
* Is HTTPS egress to Drizz's domains allowed, including the real-time connection?
* Is there a proxy that terminates long-lived connections after a fixed idle period?

## Common mistakes

| What you do                                                  | What happens                                                           |
| ------------------------------------------------------------ | ---------------------------------------------------------------------- |
| Debug a failing run for an hour before running preflight     | Preflight would have named the failing layer in 20 seconds             |
| Assume "works on hotspot, not on office wifi" is a Drizz bug | It's TLS inspection or an egress rule. Take the preflight output to IT |
| Install the corporate certificate in a browser only          | Drizz reads the macOS system store. It needs to be there               |
| Re-run preflight without fixing anything                     | Same result. Fix the topmost red row, then re-run                      |
| Ignore an amber real-time connection row                     | Runs start and then die partway. That row is the reason                |
| Reinstall the app to fix a network problem                   | Nothing changes. The network is outside the app                        |

## Next

* [Download & install](/desktop-app/download-and-install.md)
* [Updates & forced updates](/desktop-app/updates.md)
* [Report an issue](/desktop-app/report-an-issue.md)

***

*Last updated: 6 August 2026*