upgrading failure

"I have an iPhone 11 running iOS 15.6.1. I'm attempting to update it to version 16.7, but it fails every time. The typical error message I receive is: 'Unable to verify the update, Verification failed for iOS 16.7 because you are no longer connected to the internet.' I've tried being connected to Wi-Fi and without Wi-Fi but on 4G, and I still get the same message. Do you have any tips for moving forward?"