Please double check that you are using the correct email address. If you still cannot log in, try to set up a new password on the "Forgot password?" page. After entering your email address on the page, you will receive an email with a link. The link will help you to create a new password to log in with.
Should the above suggestions not solves the issue, please, if possible, take a screenshot of what it looks like when the problem occurs and contact our customer service by phone or on our web form.