remote desktop issue

up until today i could use remote desktop to access our 3 servers. today, one of the servers is not accessible (the other 2 are fine). i can ping the server name and ip but still no remote desktop. there are no firewall issues and i can remote desktop from the server in question to other servers. all appropriate services are running. as i said, tuesday everything is fine and wednesday it’s not.
any thoughts other than MS sucks!?