Ensure DNS is correctly configured and that name resolution is able to occur to and from the client machine and the domain controllers in a timely manner.
Ensure the /etc/resolv.conf is correct on the client machine.
To test name resolution for a particular on the host, you can use the nslookup command and specify the ip address of each DNS server:
nslookup -q=SRV < _ldap._tcp.dc._msdcs.yourdomain.com > < nameserver IP>
If QAS is installed on the system, another useful command to find the DNS server issue: time /opt/quest/bin/vastool -d5 info servers -d yourdomain.com -b -s \*
Add the /etc/resolv.conf option timeout:1 setting