Once installed, go to Settings > General > VPN & Device Management on your iPhone. Find your Apple ID profile and tap Trust .
If your device can't update to a newer version of iOS (for example, if it's running iOS 12.5.7), you can still install YouTube, but you might not be able to update the app through the App Store in the future, and some features might not work as expected. install youtube ios 1257 best
If you haven't "purchased" the app before or Method 1 fails, the mobile website is the most reliable way to watch videos without a jailbreak. Once installed, go to Settings > General >