iTunes and App Store wont sign in

Hello everyone, I have an iPad mini 4 and I have been having this problem in which every time I sign into my iTunes and App Store it stays as off regardless of me using the correct information. How do I know its correct you may ask? Well, I did the same with my iPhone 6 and it showed no problem whatsoever. On a side note this a repost from another one I wrote earlier today, although clearer. (I am not a native English speaker, therefore, I am sorry for any mistake)