If you have a standard, web builder, reseller or enterprise hosting account you may find that the username/password for the account is stored with the client area. Take a look on the "My Services" page.
If you do not have access to the billing account/client area, please see this article.
Once logged in, click on the hosting account in question from the list which will bring up a page of further information, in some but not all cases the password will be listed.
Be aware that the password on file may have changed since the account was created or last updated. Therefore if the password is not listed or doesn't work, it needs to be reset.
On that page you will then find the "Change Password" link on the "Actions" panel. Click on this, enter your new password (twice for confirmation) and click "Save Changes".
If you receive this error message, please contact our support team. The information we have on file for each hosting account is not always 100% accurate, particularly with account over 5 years old. A member of staff may have to correct this information for the password reset to work.