Open Directory not working for AFP authentication

Scenario:

- Running OS X Server (10.9) using FileSharing with AFP to share to multiple users.

- Currently the users login with local user accounts to gain access. I'd like to use our Open Directory server to authenticate instead (save me maintaining local users).

Issue:

- I added the OD server to Apple > System Prefs > Users > Login Options but when users attempt to login with their OD name/password, it doesn't recognize their credentials. Their local user accounts work fine and I've added their OD names to the access list for the various directories on the server.

I'm assuming I need to add the OD server somewhere else on the computer to get OS X to bind to it. Appreciate any input here.