Why can I not login to my user account?

The answer:

First, check your Internet connection, if it works correctly, then verify the correctness of the data you use to log in. In order to log in to your account, use the email address you provided during account registration and the password you set up. If you think that the data you provided is correct and you still can not log in to your user account, then you can log in through your Facebook account, if the email addresses used for registration in the websites are identical. You can also use the 'Forgot your password?' option and generate a link to set up a new password which is sent to  the email address associated with your user account.