Password Verification issue

On my IPAD I keep having to change my Apple password. After I have just finished changing it, a minute or so later it pops up saying for me to type my password into "settings". When I type in my new password that was just verified, it doesn't recognize it and I have to once again make up a new password. Why does it keep doing that? I keep getting popups on my IPAD asking me to type in my password while I am viewing sites on the internet.