How to Fix Wi-Fi Password Rejected After the iOS 27 Update

If a saved Wi-Fi password is rejected after an iOS update, start by checking the password on another device and reconnecting to the network. The timing does not prove that iOS 27 caused the problem, so work through the network and router checks before using a reset.

Reconnect safely

Confirm the password with the network owner or by connecting another device.
Turn Wi-Fi off and back on, then forget the affected network and join it again with the verified password.
Restart the iPhone and the router if other devices are also unable to join.
Try a different trusted Wi-Fi network to distinguish a phone-wide issue from one network's issue.

Use network reset last

If the problem remains, Settings provides Reset Network Settings under General, Transfer or Reset iPhone, then Reset. This removes saved Wi-Fi networks and passwords and also resets cellular, VPN, and APN settings, so record what you need before using it. Seek router or internet-provider help when only one network rejects the password.

If the Wi-Fi issue appears alongside broader iOS freezes, restarts, or update failures, Dr.Fone - System Repair provides a guided desktop workflow for iOS system issues before you consider a full erase.