Depending on how heavy the cable traffic is in your area (Medina...as in Ohio?), your modem might be timing out in its tries to get the server. If this happens, you may very well get a "server unavailable" message.
Note, cable is not a direct connection in the fashion that you may think. You are actually sharing your bandwidth with all of your neighbors or at least everyone working off the same cable hub as you. So when everyone on that hub hits the net at the same time, your speed might actually drop to below that of dial up.