Getting an "authentication error occurred" after connecting to WiFi.

[Android Central Question]

Since I installed the latest update to my Samsung galaxy S6 I can no longer remain connected to my home WiFi. It'll connect briefly and then drop off with the message "authentication error occurred".
The password hasn't been changed on the WiFi and we've contacted 2degrees to try and resolve but they believe it to be because of the latest software update.
Can I uninstall this update to get my WiFi connection back?
Or is there some other fix I can implement?

 

[B. Diddy]

Welcome to Android Central! Try rebooting the router by unplugging its power for 10 seconds.

 

[Dano1200r]

Also, try: Forget the network, then repair to it.