Open WiFi settings by going into the Settings App > Wi-Fi > Tap the Wi-Fi that’s having issues and select “Forget”.
Re-open the WiFi Setting and locate the Wi-Fi name you’re attempting to connect to. Select “Connect” (enter the password if necessary).
If it continues to reject the password, verify the password on a separate device such as the Computer or another device.
*Password Tip, be sure the password is being entered with correct capitalization.