I use mustang server, but i can login successfuly without any problems, From what i can see it looks like you are using email as the username, if so you should login to member area https://my.hawkhost.com/ instead directly to cpanel (cpanel does not use email as the username). On member area, you will find the username and password used to login into cpanel (my service) you can also click the button there to login into cpanel without having to entering username password manually.
Hope it helps