# They can't ping on any port or ssh in? Or is it that they can't see the samba shares?
# there is a line in smb.conf
# interfaces = lo eth0 192.168.1.$$$/24
# if your ip has changed but that ip hasn't been updated your shares may not be visible
# also check
systemctl status nmb.service
systemctl status smb.service
# recheck your firewall & selinux settings
# all of these should be installed
yum list samba samba-client samba-common samba-winbind-clients
# have you performed any updates or moved this box to a different branch of the network?