This error is so common. Usually when it tells you its wrong, its because it is.
you username is your full mailbox name so firstname.lastname@example.org
Its important to make sure you are using the right password on ALL of your devices. Our servers are designed to stop any hack attempts and if you try too many times with the wrong password, the server will ban you and you will have to call the office to have support unblock you.
One remedy is to log into your control panel and reset the mailbox password. But if you do that you will need to update all the devices for this to take effect. It is advisable to shut off all of your devices if you are required to reset your password as to not cause yourself to be blocked because the incorrect password is being sent from a phone or tablet.
If you need help please call the office and our support staff will help you.