LDAP Error Timeout

I20190705-14:04:26.256(-7) server.js:199 LDAP ➔ Connection.error connection time out 1000
I20190705-14:04:26.292(-7) server.js:199 LDAPHandler ➔ error Error: Timeout at Timeout.setTimeout (app/ldap/server/ldap.js:179:14) at ontimeout (timers.js:498:11) at tryOnTimeout (timers.js:323:5) at Timer.listOnTimeout (timers.js:290:5)
I20190705-14:07:51.033(-7) Unloaded the Apps Framework.
I20190705-14:08:18.022(-7) server.js:199 LDAP ➔ Connection.error connection time out 1000
I20190705-14:08:18.022(-7) Error: Timeout at Timeout.setTimeout (app/ldap/server/ldap.js:179:14) at ontimeout (timers.js:498:11) at tryOnTimeout (timers.js:323:5) at Timer.listOnTimeout (timers.js:290:5)

Rocket.Chat Version: 1.0.3
NodeJS Version: 8.11.4 - x64
MongoDB Version: 3.6.12
MongoDB Engine: mmapv1
Platform: linux

I had a previous instance of RocketChat that was running perfectly fine til one day, I had someone complain they could not log on to OwnCloud (Rocketchat / Owncloud running as apps on a Univention Corporate Server). The tcp and host A DNS entries were missing for the Univention server on our domain DNS. I recreated the DNS entries above. Owncloud issue was resolved however I’ve had issues ever since with RocketChat (users who stayed logged in were not affected but anyone trying to log in were denied access). I uninstalled RocketChat from the Univention server and reinstalled. Now I cannot get LDAP to connect at all.

Using DNS names and IP addresses do not work for the LDAP host entry. In RocketChat, I get “Error Timeout” each time I test the connection. Above are the logs when I “view logs” in the GUI. OwnCloud runs on the same server and connects to LDAP fine. RocketChat seems to have an issue talking to servers internally on the same network.

What exactly went wrong here?