You may be having a networking or Internet connectivity issue. Try restarting your phone first. Then, try the update while you are closer to your WiFi router. Or, try the update using a friends WiFi.
Trying to update my phone to iOS 11 but it keeps saying error updating, try again later but only to get the same results as before.
2 replies
You may need to update via a wired connection using iTunes. Sometimes, a wireless one won't take for an array of reasons
What does it mean when my iPhone says error updating iOS?