Since you said you were able to connect and play once I will assume your client is compatiable with the server. Given what you are describing and the fact you can play on other servers I would run a tracert on the legacy of zek servers ip address to check to for dropped connections along the hops from your computer to that server.
This is a brief explanation of tracert in case you don't know how to use it.
Code:
http://kb.iu.edu/data/aihy.html