Can’t log into Domain with Tcpip

My users are suddenly having to wait 20 seconds or so to log in to my nt4 server. Initially this was nearly immediate. In troubleshooting this I decided to remove Ipx from one workstation and after I rebooted I was given the No Domain to log into error. I checked a few more clients and it was the same for all. I can ping the server from anywhere but I can’t log in (no domain found) When Ipx is loaded again the logins work but work slowly. The server’s ip, netmask, gateway, etc etc are all correct and the machine uses the internet without a problem. Any solutions?