You can see the error message on the bottom of the login page:
Warning: Unknown: open(/var/cpanel/php/sessions/ea3/sess_1135a974ef974167d98e22b04d586287, O_RDWR) failed: No such file or directory (2) in Unknown on line 0
Warning: Unknown: Failed to write session data (files). Please verify that the current setting of session.save_path is correct (/var/cpanel/php/sessions/ea3) in Unknown on line 0
This tells you that the session.save_path is set wrong in the php.ini file. Report this to your hosting provider and they should be able to fix it for you.