My phone is Huawei P9 Gold and my Tablet is Samsung Galaxy S 10.1.
I woke up this morning and tried to connect my phone first to wifi but it won't connect. So I restarted my phone and it still won't work. I reconnect my phone to wifi but it says "Incorrect password", so I typed my password and it's still says the same thing. I'm very sure that the password I typed was correct. Also, the same thing happened to my tablet.
Read more: https://samsungus.org/qa/i-can-t-connect-my-wi-fi-to-my-phone-and-tablet.html