How to Fix WI-Fi "Authentication Error Occurred" on Android
Have you ever tried to connect to a Wi-Fi network you have connected to before, but couldn't this time. Instead of logging in, the only thing you see is an "Authentication error".
Make sure that you are connecting to the correct network and make sure you entered the correct password. If you're still getting the authentication error message try the tips outlined in this article to reconnect to your Wi-Fi network.
Use Airplane Mode
When you enable Airplane Mode all radio-frequency signal transmission on your phone is disabled. This disables your Wi-Fi, however, you can re-enable it manually.
To activate Airplane mode simply swipe down from the top of your display and turn off the mobile network and Wi-Fi. Then turn on airplane mode and re-enable the Wi-Fi option. If your phone manages to connect to the Wi-Fi network without any problems, then you can turn airplane mode off again. If this doesn't work for you try the next method.
Reset your Wi-Fi connection
One of the most common solutions to this problem is to disable your Wi-Fi connection and reconnect. Simple, but surprisingly effective. To turn off your Wi-Fi go to your device's Settings and select Wi-Fi. Choose the network you cannot connect to under Wi-Fi Networks. Hold down on the network and a small window with the options to either forget the network or modify network config will appear.
Select the Forget Network option and move away from the router until you're only getting one bar signal. When you have that single bar, re-connect to the network again.
Use a different wireless network setting
You could be having an authentication problem because of an IP conflict. If that's true then the best thing you can do is modify the wireless network setting from the default DHCP to Static IP.
You can do this quite easily by going to Settings and selecting the Wi-Fi option, then holding down on the network until you see the same window I mentioned above, but this time tap on modify network config instead of the forget the network option.
Select the advanced options and find the option that says DHCP. Tap on it and you will there is only one other option, which is the Static option. Tap on that, and you will see an IP address field. When it is displayed, save the info you see in the static IP address field and erase it. Enter the same data again and select save.
Refresh your network settings
If none of the previous options have resolved the authentication issue, then it looks like you will have to refresh everything. That means the Bluetooth, mobile network, and wireless network simultaneously.
To do so navigate to Settings > Backup & reset > Network reset and select the Reset Settings. The process won't take long. When it's over you should try to log into the network that's giving you trouble. You should be able to connect to it now.
Note: Refreshing your network setting will wipe the data from all the connections you made before.