well, sorry to say that mbl server is almost dead these days, because of two reasons.
One is loadshedding and other is that mbl is not yet upgraded to patch 1.0.4.4 since KSO server is, so most of the people have done it and they cant play on old one.
But it will be fixed in few days and it will active especially during winter holidays. In the meantime you can play on these servers:
http://css.setti.info/servers/list-tf2.php
And i usually play on this server:
194.44.21.67:27016
This server also plays on custom maps, when required download maps from fpsbanana.com
BTW at this moment i am coming on MBL, so join now, i will let you know few things out there.
Come on.