Unable to update my iPhone X to iOS 17

Your tag line suggests you have an iPhone X and if you do, it is not capable of running iOS 17. If you need iOS 17 or higher, then you'll need to retire your older phone and buy a newer, more modern iPhone.

The iPhone X (as shown in your device line) cannot update past iOS 16.7.10, that is the most current iOS version it supports. It is not compatible with iOS 17 or 18.

If you have iOS 16 now and you cannot update to iOS 17, your phone is not compatible with iOS 17 or iOS 18.

That means that you likely have an iPhone 8, iPhone 8 Plus or iPhone X.

If you want to update to iOS 18.....(iOS 17 is no longer available as an update)......you will need a new phone.