Why cant i connect to wifi on my IPad Mini

When i put my password in my Wifi Network..

All it does is show me the loading sign, But it never gave me the blue check mark indicating that's it's connected

But when i try connecting to my mom's hot spot it works..

My Ipad Mini is IOS 8.2

i have tried resetting my network settings

updating it to it's current IOS 8.2

turning off my Ipad and turning it back on

Why is that?

and how should I fix this?