Solved: Lenovo P780 Hand Phone's Authentication Problem

Suddenly on April 27th my Hand Phone, Lenovo P780 with Android Jelly Bean cannot connect through WLAN (Wi Fi) at my home. Though the signal is good and I input the right password, it cannot connect. The message is: Authentication Problem.

But in my Office, my hand phone is connected through the Wi Fi without problem. Then after backup the data, I reset my Hand Phone. Above the battery there is a tiny red button. I push it with pen.

After I went home, I can connect to the Wi Fi without problem. But I don't know if the router there is reset or not.

The solution is: reset your hand phone. If it's not working: reset your wi fi. It means, turn it off for 1 minute, then turn it on again. Simple.