errors where encountered while processing slapd

I'm trying to setup an ldap server on ubuntu 16.04. During installation of ldap-utils and slapd I get the following:

Setting up slapd (2.4.42+dfsg-2ubuntu3.2) ...
  Moving old database directory to /var/backups:
  - directory unknown... done.
  Creating initial configuration... done.
  Creating LDAP directory... done.
Job for slapd.service failed because the control process exited with error code. See "systemctl status slapd.service" and "journalctl -xe" for details.
invoke-rc.d: initscript slapd, action "start" failed.
● slapd.service - LSB: OpenLDAP standalone server (Lightweight Directory Access Protocol)
   Loaded: loaded (/etc/init.d/slapd; bad; vendor preset: enabled)
   Active: failed (Result: exit-code) since Fri 2018-06-01 15:04:58 CDT; 4ms ago
     Docs: man:systemd-sysv-generator(8)
  Process: 3107 ExecStart=/etc/init.d/slapd start (code=exited, status=1/FAILURE)

Jun 01 15:04:58 TBG-Magic systemd[1]: Starting LSB: OpenLDAP standalone server (Lightweight Directory Access Protocol)...
Jun 01 15:04:58 TBG-Magic slapd[3107]:  * Starting OpenLDAP slapd
Jun 01 15:04:58 TBG-Magic slapd[3115]: @(#) $OpenLDAP: slapd  (Ubuntu) (May 30 2017 19:20:53) $
                                               buildd@lgw01-18:/build/openldap-JXEADB/openldap-2.4.42+dfsg/debian/build/servers/slapd
Jun 01 15:04:58 TBG-Magic slapd[3115]: daemon: bind(9) failed errno=98 (Address already in use)
Jun 01 15:04:58 TBG-Magic slapd[3107]:    ...fail!
Jun 01 15:04:58 TBG-Magic systemd[1]: slapd.service: Control process exited, code=exited status=1
Jun 01 15:04:58 TBG-Magic systemd[1]: Failed to start LSB: OpenLDAP standalone server (Lightweight Directory Access Protocol).
Jun 01 15:04:58 TBG-Magic systemd[1]: slapd.service: Unit entered failed state.
Jun 01 15:04:58 TBG-Magic systemd[1]: slapd.service: Failed with result 'exit-code'.
dpkg: error processing package slapd (--configure):
 subprocess installed post-installation script returned error exit status 1
Setting up ldap-utils (2.4.42+dfsg-2ubuntu3.2) ...
Processing triggers for libc-bin (2.23-0ubuntu10) ...
Processing triggers for systemd (229-4ubuntu21.2) ...
Processing triggers for ureadahead (0.100.0-19) ...
Processing triggers for ufw (0.35-0ubuntu2) ...
Rules updated for profile 'OpenSSH'
Skipped reloading firewall
Errors were encountered while processing:
 slapd
E: Sub-process /usr/bin/dpkg returned an error code (1)

The logs from running journalctl -xe look like this:

-- Subject: Unit slapd.service has begun start-up
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit slapd.service has begun starting up.
Jun 01 15:16:33 TBG-Magic slapd[7009]:  * Starting OpenLDAP slapd
Jun 01 15:16:33 TBG-Magic slapd[7018]: @(#) $OpenLDAP: slapd  (Ubuntu) (May 30 2017 19:20:53) $
                                               buildd@lgw01-18:/build/openldap-JXEADB/openldap-2.4.42+dfsg/debian/build/servers/slapd
Jun 01 15:16:33 TBG-Magic slapd[7018]: daemon: bind(9) failed errno=98 (Address already in use)
Jun 01 15:16:33 TBG-Magic slapd[7018]: daemon: bind(9) failed errno=98 (Address already in use)
Jun 01 15:16:33 TBG-Magic slapd[7018]: slapd stopped.
Jun 01 15:16:33 TBG-Magic slapd[7018]: connections_destroy: nothing to destroy.
Jun 01 15:16:33 TBG-Magic slapd[7009]:    ...fail!
Jun 01 15:16:33 TBG-Magic systemd[1]: slapd.service: Control process exited, code=exited status=1
Jun 01 15:16:33 TBG-Magic systemd[1]: Failed to start LSB: OpenLDAP standalone server (Lightweight Directory Access Protocol).
-- Subject: Unit slapd.service has failed
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
-- 
-- Unit slapd.service has failed.
-- 
-- The result is failed.
Jun 01 15:16:33 TBG-Magic systemd[1]: slapd.service: Unit entered failed state.
Jun 01 15:16:33 TBG-Magic systemd[1]: slapd.service: Failed with result 'exit-code'.

After running sudo apt-get remove --purge slapd and reinstalling it. I still get the same error upon installation. How do I fix this issue?

The issue was that something was already using the address, as you can see from the log files here:

Jun 01 15:16:33 TBG-Magic slapd[7018]: daemon: bind(9) failed errno=98 (Address already in use)

I realized that earlier I had installed samba and smbldap-tools. Removing both of those with sudo apt-get remove --purge samba smbldap-tools results in the following:

serveradmin@TBG-Magic:~$ sudo service slapd status
● slapd.service - LSB: OpenLDAP standalone server (Lightweight Directory Access Protocol)
   Loaded: loaded (/etc/init.d/slapd; bad; vendor preset: enabled)
   Active: active (running) since Fri 2018-06-01 15:21:19 CDT; 23s ago
     Docs: man:systemd-sysv-generator(8)
  Process: 8708 ExecStart=/etc/init.d/slapd start (code=exited, status=0/SUCCESS)
    Tasks: 3
   Memory: 2.5M
      CPU: 18ms
   CGroup: /system.slice/slapd.service
           └─8717 /usr/sbin/slapd -h ldap:/// ldapi:/// -g openldap -u openldap -F /etc/ldap/slapd.d

Jun 01 15:21:17 TBG-Magic systemd[1]: Starting LSB: OpenLDAP standalone server (Lightweight Directory Access Protocol)...
Jun 01 15:21:17 TBG-Magic slapd[8708]:  * Starting OpenLDAP slapd
Jun 01 15:21:17 TBG-Magic slapd[8716]: @(#) $OpenLDAP: slapd  (Ubuntu) (May 30 2017 19:20:53) $
                                               buildd@lgw01-18:/build/openldap-JXEADB/openldap-2.4.42+dfsg/debian/build/servers/slapd
Jun 01 15:21:19 TBG-Magic slapd[8717]: slapd starting
Jun 01 15:21:19 TBG-Magic slapd[8708]:    ...done.
Jun 01 15:21:19 TBG-Magic systemd[1]: Started LSB: OpenLDAP standalone server (Lightweight Directory Access Protocol).