De acordo com man ldap.conf
:
URI <ldap[si]://[name[:port]] ...>
The URI scheme may be any of ldap, ldaps or ldapi, which refer to LDAP over TCP, LDAP over SSL (TLS) and LDAP over IPC (UNIX domain sockets), respectively.
Portanto, altere uri ldapi:///ldap.example.com
para uri ldap:///ldap.example.com
e tente novamente.