How to resolve "unable to determine enabled services from ldap"

After restarting the zimbra service or rebooting the server, you may encounter the following error when starting ldap.

Starting ldap...Done.
Unable to determine enabled services from ldap.
Enabled services read from cache. Service list may be inaccurate.

This problem can have several causes, as listed below.

• Permissions on /opt/zimbra. Run the following command to fix them.

  service zimbra stop
  chown -R zimbra:zimbra /opt/zimbra
  /opt/zimbra/libexec/zmfixperms -verbose
  service zimbra start

• Incomplete DNS configuration. Add any missing information. How to check:

  cat /etc/hosts 
  host `hostname` 
  dig yourdomain.com mx
  dig yourdomain.com any

• The certificates on the server have expired. To check, run:

  /opt/zimbra/bin/zmcertmgr  viewdeployedcrt all

  Check the expiration date under “notAfter”. If the certificates have expired, create new certificates using the following steps.

  Reading note: The Thai line in the following block means “Delete certificates”.

  
  Stop zimbra
  su - zimbra -c 'zmcontrol stop'
  ลบ certificates
  rm -rf /opt/zimbra/ssl/*
  rm -rf /opt/zimbra/ssl/.rnd
  
  /opt/zimbra/java/bin/keytool -delete -alias my_ca -keystore /opt/zimbra/java/jre/lib/security/cacerts -storepass changeit
  /opt/zimbra/java/bin/keytool -delete -alias jetty -keystore /opt/zimbra/mailboxd/etc/keystore -storepass `su - zimbra -c 'zmlocalconfig -s -m nokey mailboxd_keystore_password'`
  
  vi /opt/zimbra/bin/zmcertmgr
  
  # Find line
  # SUBJECT="/C=US/ST=N\/A/L=N\/A/O=Zimbra Collaboration Suite/OU=Zimbra Collaboration Suite/CN=${zimbra_server_hostname}"
  # and change to your company name
  
  # then find and change you want value days expire cert validation_days=365 to validation_days=3650
  # save /opt/zimbra/bin/zmcertmgr
  
  /opt/zimbra/bin/zmcertmgr createca -new
  /opt/zimbra/bin/zmcertmgr deployca -localonly
  /opt/zimbra/bin/zmcertmgr createcrt self -new
  /opt/zimbra/bin/zmcertmgr deploycrt self
  
  su - zimbra -c 'zmcontrol start'
  
  /opt/zimbra/bin/zmcertmgr deploycrt self
  /opt/zimbra/bin/zmcertmgr deployca
  
  su - zimbra -c 'zmupdateauthkeys'
  /opt/zimbra/bin/zmcertmgr viewdeployedcrt</li>