If the iHerb app is closing automatically on your iPhone, you can follow these step-by-step troubleshooting methods to address the issue.

1. Force Close the iHerb App

- Double-click the Home button or swipe up from the bottom of the screen to open the app switcher.
- Locate the iHerb app and swipe it up to close it.
- Reopen the app to see if the issue persists.

2. Restart Your iPhone

- Press and hold the power button until the slider appears.
- Slide to power off your device completely.
- After the device has powered down, press and hold the power button again until the Apple logo appears.

3. Check for iOS Updates

- Go to Settings > General > Software Update.
- If an update is available, tap Download and Install.
- Keeping your iOS updated ensures compatibility with apps.

4. Update the iHerb App

- Open the App Store.
- Tap your profile icon at the top of the screen.
- Scroll down to see pending updates. If iHerb has an update available, tap Update.

5. Reinstall the iHerb App

- Press and hold the iHerb app icon until it wiggles.
- Tap the “X” to delete the app.
- Once deleted, go to the App Store and search for iHerb to reinstall it.

6. Reset All Settings

- Go to Settings > General > Transfer or Reset iPhone > Reset > Reset All Settings.
- This will reset system settings without deleting your data, which can sometimes resolve conflicts causing app crashes.

7. Contact iHerb Support

- If the issue persists after these steps, consider reaching out to iHerb support.
- They may provide additional troubleshooting specific to their app.

By following these steps, you should be able to resolve the crashing issue with the iHerb app. If problems continue, it may be worth checking for any broader iOS issues or other apps misbehaving, which could indicate a deeper system issue.

For further reference on troubleshooting app crashes, you can also look at related resources such as Apple's official support page - learn more.