This error occurs if you did not validate your email address.
When you first sign-up you are sent an email to verify. If you do not click the link in the email then your account is not verified and you will get the error "the system does not recognize the user name." when you try and login.
Please review this KB for issues with emails getting flagged as SPAM: https://ussbaforgiveness.zendesk.com/hc/en-us/articles/360060242752-I-m-not-getting-the-registration-or-password-reset-email-