The first thing to do before you login is make sure you are running the latest software on your iPad.
The login details are case sensitive and sometimes they can self - predict so input them carefully (the fact you can now see what you are writing should help!).
It is also important that you are connected to the internet when you login. If you are still not having success, there may be a firewall issue so please get in contact with us as we have a number of steps to follow with your IT department to open a few ports.
Don't worry, we haven't had anyone who can't login at all.