Hi there! I'm here to help with your Timeshifter app issue. I understand that it hasn't been working for the past few hours while everything else on your iPhone seems fine. Let's work together to figure this out.

1. Force Close the App: First, let's try a simple step. Close the Timeshifter app completely. You can do this by swiping up from the bottom of your screen (or double-clicking the home button if your iPhone has one) to show all the running apps. Then, swipe up on the Timeshifter app to close it. Once it's closed, try reopening it.

2. Restart Your iPhone: If that doesn’t work, a restart might help. To do this, press and hold the side button and the volume button until you see the power off slider. Slide it to turn off your iPhone. After it’s off, turn it back on by pressing the side button again.

3. Check for App Updates: Sometimes, apps need to be updated to work properly. Check the App Store for any available updates for the Timeshifter app.

4. Reinstall the App: If the app still isn’t opening, consider uninstalling and reinstalling it. Find the Timeshifter app on your home screen, press and hold it until it wiggles, then tap the "X" to delete it. After that, go to the App Store and download it again.

5. Check for iOS Updates: It's also good to ensure your iPhone is running the latest version of iOS. Go to Settings > General > Software Update and see if there’s an update available.

If these steps don't resolve the issue, please let me know, and we can explore additional options or check if there might be a server problem affecting the app. Are you able to try these steps?