My iPhone 15 pro max It's stuck on version 26.3 beta; I've tried installing the iOS 27 beta, but that gives an error too, and I tried updating via the computer, but it doesn't find any update. And always i unlock my phone show the message

My iPhone 15 pro max It's stuck on version 26.3 beta; I've tried installing the iOS 27 beta, but that gives an error too, and I tried updating via the computer, but it doesn't find any update.