Got the solution from here:
openfire AD integration with Zentyal
Basically I had the DN information wrong for the Administrator. I figured it was something like that but I didn't know how to check the DN information. The command I needed (at least on a linux box running a samba4 AD DC) was:
ldbsearch -H /var/lib/samba/private/sam.ldb > ldbsearchresults.txt
I then searched the result file for my Administrator name and I discovered that the DN should be something more like:
DC=Chat Server,OU=Servers,DC=local,DC=mydomainname,DC=com
