Openldap trying to setup mozillaAbPersonAlpha.schema
 

I'm trying to Include mozillaAbPersonAlpha.schema in to Openldap 2.5.4 on Ubuntu server 20.04.2

The steps I have taken
1) mkdir /tmp/ldapworkingdir
2) cd /tmp/ldapworkingdir/
3) touch ldap.conf
4) echo "include /etc/ldap/schema/mozillaAbPersonAlpha.schema" > ldap.conf
5) slaptest -f ldap.conf -F .
6) the error message
60b0fc5f /etc/ldap/schema/mozillaAbPersonAlpha.schema: line 148 objectclass: AttributeType not found: "c"
slaptest: bad configuration directory!

I have tried look for example of how to setup Thunderbird address book but with no look.
I do hope someone can help.

Bob G