All Domain controllers servers in use are not responding

[Di_marcello]

greetings,

I have a problem that occurred sinds I installed sp2 for exchange 2000
Many times in an hour it can't find the domain controller (global catalog
server)

This is the event log message: Process MAD.EXE (PID=1836). All Domain
Controller Servers in use are not responding: server.server.com

The problem is that when this occurs the mail client cannot connect to OWA
and in outlook it gets a message, retrieving from mail server. mails get
stuck in the outbox and you cannot work with your mail for a minute. This
for me is not done. can anybody help me with this.