A focused troubleshooting guide for the most common reasons a Rork preview fails on your iPhone: connectivity, version mismatches, and bundle errors in Expo Go.
A Rork app that previews fine one moment and refuses to load the next is frustrating, but the causes are usually mundane. Expo Go loads your app over the network, so most failures are connectivity or version issues, not broken code.
This guide works through the common causes in order of likelihood. Start at the top and stop when it loads.
Resist the urge to rewrite your app first. A preview failure rarely means your code is wrong; it usually means the bundle never reached the phone.
Work methodically. Changing several things at once makes it impossible to know what actually fixed it.
The pattern of the failure is a clue. An app that never appears at all points to connectivity or version problems, while an app that loads and then crashes points to code or an unsupported module — two different paths to investigate.
Expo Go needs to reach your project, which most often requires your phone and the host to be on the same network. This is the single most common cause of preview failures.
Confirm your iPhone is on the same Wi-Fi, not on cellular data. A phone that silently dropped to cellular won't find a local development server.
Guest networks and corporate Wi-Fi often block the device-to-device traffic Expo relies on. If you're on one, switch to a normal home network or a personal hotspot to test.
After changing networks, fully reload the project in Expo Go rather than assuming it will reconnect on its own.
An outdated Expo Go app is a frequent culprit. Each Expo Go version supports specific Expo SDK versions, and a mismatch shows up as a load failure or a version warning.
Update Expo Go from the App Store to the latest version. Then check the Expo SDK version your Rork project targets.
If the project uses an SDK that your installed Expo Go doesn't support, you'll get errors. Align them — typically by updating Expo Go, or by keeping the project on a supported SDK.
This mismatch is especially common after the app sits unused for a while and Expo Go has since updated. A quick version check saves a lot of guessing.
Stale bundles cause weird, inconsistent failures. A cached older build can refuse to load or show outdated screens.
Force a fresh reload of the project rather than relying on the last cached version. In Expo Go, fully close and reopen the project entry.
If Rork offers a way to regenerate or restart the preview session, use it to produce a clean bundle. A fresh session sidesteps a corrupted in-flight build.
Quit and relaunch Expo Go entirely if reloads aren't helping. Clearing the app from memory resolves a surprising number of phantom issues.
When the app does load far enough to show an error, read it — don't dismiss it. A red error screen usually names the real problem.
A missing module points to a dependency that isn't installed or isn't supported in Expo Go. A syntax error points to a specific file and line.
Note whether the error is in your code or in the bundling step. Bundling errors are environment issues; runtime errors in your code are something to prompt Rork to fix.
Copy the exact message when you ask for help or re-prompt. 'It doesn't work' is unsolvable; the literal error text is actionable.
Pay attention to the first line of a stack trace too. The deepest frame often points at a library, but the first frame usually points at the screen or component you most recently changed, which is where to look first.
Expo Go can only run native code that's built into its runtime. If your app added a custom native module that Expo Go doesn't include, it will fail to load there.
This is a real limitation, not a bug. Expo Go is a convenience runtime, and not every native dependency fits inside it.
The fix is a development build, which compiles your specific native dependencies into a custom client. It's more involved than Expo Go but supports the full native surface.
If you only recently started seeing load failures after adding a feature, an unsupported native module is a prime suspect.
If you're still stuck, separate the two possibilities. Does a fresh, minimal Rork app load in Expo Go on this phone and network?
If a minimal app loads but yours doesn't, the problem is in your project — a dependency, a bundling error, or an unsupported module. If even a minimal app fails, the problem is environment or network.
This split saves hours. It tells you whether to debug code or to debug connectivity.
Keep that minimal app around as a known-good baseline. It's the fastest way to test whether a future failure is local to your project.
When a preview fails, running a fixed checklist beats poking at random. Order matters, because the cheapest, most common fixes come first.
Start with the network: same Wi-Fi, not cellular, and not a restrictive guest or corporate network. Then update Expo Go and confirm it supports your project's SDK version.
Next, force a clean reload and, if needed, restart a fresh preview session to clear a stale bundle. Only after those do you read the on-screen error and consider native-module limits.
If the checklist still leaves you stuck, fall back to the minimal-app test to decide whether you're debugging your project or your environment. That single split decides where the next hour of effort should go.
Expo Go is ideal for fast iteration, but it isn't the final word. Some apps simply need more than it can run.
If you repeatedly hit native-module limits, it's a signal to graduate to a development build. That's a normal step in a maturing project, not a workaround.
For final pre-release testing, build a real binary with EAS and test that. The shipped app can behave differently from the Expo Go preview.
Think of Expo Go as the quick-look tool and EAS builds as the truth. When the preview and the build disagree, trust the build.
Expo Go typically needs your phone and the project host reachable on the same network. Cellular data breaks that path, so stay on the same Wi-Fi or use a personal hotspot.
It usually appears as a load failure or a version warning when Expo Go's supported SDK range doesn't include the version your project targets. Update Expo Go or align the project's SDK.
You may have added a native module Expo Go can't run. Those require a development build that compiles your specific native dependencies into a custom client.
Test whether a fresh minimal Rork app loads on the same phone and network. If it loads and yours doesn't, the issue is in your project; if it also fails, it's the environment.
Expo Go is great for iteration, but do final pre-release testing on a real EAS build, since the shipped app can behave differently from the Expo Go preview.