Users can't login

I have a problem where none of our Active Directory users can login to our Spark server. We receive an error that reads:

Can’t connect to the server; invalid name or server not reachable

The server is a VM running CentOS and I have confirmed the server is up and I can login at the console using the root account but after that I am at a loss. Our “linux” guy is unavailable. Any help would be appreciated!

Can you ping the ldap server hostname in the openfire configuration from the system running Openfire?