It is not possible to log in with an iPad or a tablet
If you use an iPad or a tablet and you use the function "case sensitive", please pay attention on that accidentally caps on the first character position of your password. This you can only check by paying attention or the "shift" key lights up if you are going to fill in the password.
If you want to change this setting: “case sensitive” turn off, then choose ‘settings – general - case sensitive- and turn this off.
Be careful! It is possible that your settings screen is not the same as the example. Then you have to check the manual of your tablet.