LDAP; confusion

Hello, I hope all is well.

Two issues that I am grappling with.

One: Is this a true statement: (AIX, LDAP configured), even if authentication is configured with LDAP, the system would still need to be authenticated against local (/etc/passwd); incase of network failure?

Two: I can log on directly on the server which is using LDAP, however, from my application same ID is denied access with authentication failed.

Lot of googling and searching here, I have come to two reasons, shadowupdatelast on client may not be configured since the debug output of application's authentication module reports "password expired" when validating against maximage=13.

Second, how do I find out which schema LDAP is using? I so far learned about lsldap -a <uid> or the secldapclntd, but have no clue to how to leverage these commands or if there is a better way to get the info.

Kindly guide as to how best to proceed.

Thanks in advance,

cheers.