Not sure how useful that was..
But, some time ago... RedHat 6 I think it was, they disabled the ability to login as root via telnet.
I'm not entirely sure how / if you can turn it back on, mind.. but this is expected behaviour. Ideally you should use ssh, or telnet as a user and su.
It prevents things like brute-forcing your root password, as you can lock out a user who's being hacked (via telnet), but can't ideally do that for root.