Zimbra error - Unable to determine enabled services from ldap

Symptoms: Zimbra users unable to log in to webmail, admin user unable to log into web interface, error "Unable to determine enabled services from ldap" if issuing command
$ opt/zimbra/bin/zmcontrol start

Cause: Zimbra's internal certificate has expired

Fix (as root):

# /opt/zimbra/bin/zmcertmgr createca -new
# /opt/zimbra/bin/zmcertmgr createcrt -new -days 365
# /opt/zimbra/bin/zmcertmgr deploycrt self
# /opt/zimbra/bin/zmcertmgr deployca
# su zimbra
$ /opt/zimbra/bin/zmcontrol restart