Have a couple different depts that connect to a citrix server. For
one, it works like a champ.

For the other one (just got stuff set up for it last week), when they
try they get the error:

Cannot connect to the Citrix Metaframe server, Protocol Driver error.

Weird thing is, they connected just fine yesterday, now today, it
doesn't work.

What gives? What do I need to check?