Hi. I don't have login to your panel of course, but when I try to login with wrong credentials, it shows the error message:
If you are not getting any error message on "correct" login, it means there is something wrong with your
session save path (the path assigned by your hosting where PHP login "sessions" are stored). I have seen this before. The reason you don't get any error message, is because the login is correct, and then you are "forwarded" to the X3 control, but since the login is not "stored" in sessions, it redirects back to the login page again. Essentially, either 1) Session path is not writeable, or 2) Your hosting account storage is full.
To diagnose in depth from here, I would need FTP login.