Hope you are doing fine below is the DataDomain Operating System Administration Guide which talks about how to setup LDAP in order to add an Openldap server page 113+, there are no specific information out there so I would recommend to kindly open a case directly with backup/dd team to get a faster answer if needed.
i have read the manual and open a ticket. No one seems to know exactly what to do. This seems to be not documented properly. I have check the logs and see that the bind user was able to search the ldap.