My iPhone screen isn't rotating between portrait and landscape mode

Not all apps support rotating the screen between portrait and landscape modes. Some apps are designed to work only in one orientation, either portrait or landscape, depending on their intended use or design.

For example, many apps are primarily designed for portrait mode, like messaging apps or social media feeds, while some games and video apps might support landscape mode for a better viewing experience.

If the issue is specific to certain apps and not affecting the overall system behavior, it's likely that those apps are designed to function in only one orientation. However, if you're experiencing this problem across multiple apps that should support rotation, it could indicate an issue with your device's settings or software. In that case, the troubleshooting steps mentioned earlier might help to resolve the problem.

If your iPhone 12 Pro isn't rotating between portrait and landscape mode as expected, there are a few things you can check and try to fix the issue:

1. Check if the portrait orientation lock is enabled. You can do this by swiping down from the top-right corner of the screen (or up if you're using an iPhone with Face ID) to access the Control Center. Look for a lock icon with a circular arrow around it. If it's highlighted in white or orange, tap it to turn it off. When it's off, the screen should rotate freely.
2. Sometimes, a simple restart can resolve temporary software glitches. Turn off your iPhone, wait for a few seconds, and then turn it back on.
   1. Restart the device. That's it.
   2. Still not solved --> Force restart iPhone - Apple Support
3. If the issue persists, you can try resetting all settings on your iPhone. This will not erase your data but will reset all personalized settings to their default values. Go to Settings > General > Transfer & Reset > Reset > Reset All Settings and confirm the action. Note that you will need to reconfigure your settings afterward. All settings—including network settings, the keyboard dictionary, the Home screen layout, location settings, privacy settings, and Apple Pay cards—are removed or reset to their defaults. No data or media are deleted.
   1. Reset All Settings: Return iPhone settings to their defaults - Apple Support:- Return iPhone settings to their defaults
   2. You can return settings to their defaults without erasing your content.
   3. If you want to save your settings, back up your iPhone before returning them to their defaults. For example, if you’re trying to solve a problem but returning settings to their defaults doesn’t help, you might want to restore your previous settings from a backup.
4. Make sure you have the latest updates installed.
   1. Update Over-the-Air (OTA) —> Update your iPhone or iPad - Apple Support (IN)
   2. Update using iTunes/Finder —> Update your iPhone, iPad, or iPod touch - Apple Support (IN)

If none of the above steps resolve the issue, it is recommended to reach out to Apple Support or visit an authorized service center for further assistance. They can provide specific guidance based on your device model and iOS version.