Can someone explain to me this LDAPS certificate requirement?

Can someone explain to me this LDAPS certificate requirement?

I'm trying to make an LDAP connection from Service Desk to our domain controller ldaps://servername.domainname:636 and when I click Save and Import, I get the following error:

FAILURE: Domain Controller saved successfully, but error occurred while trying to connect to LDAP Server in secured mode. You need to import the LDAP server certificate for LDAP mode. Click here to generate the certificate.

Certificate generation / signing / installation is not a foreign concept to me. I have Active Directory Certificate service running.  I've already issued valid, trusted SSL certificates for the web ui of Service Desk, and that works fine.

But this LDAPS thing is confusing the heck out of me.  The directions in that link say to basically download these tools to create a local, self-signed certificate with a certain name, throw it in the jre/lib/security folder and restart the service. 

WHAT? This obviously isn't a requirement of my LDAPS server for ServiceDesk to have any kind of certificate.  I'm using LDAPS from other servers, namely Zabbix, and there was no certificate involved there.  What on earth is this certificate for?