LDAP Network Account Logins in Mavericks
It's possible that you need to set the Authentication Search Path inside of Directory Utility -> Search Policy -> Authentication...Make sure "Search" says "Custom Path", and that your Active Directory domain is listed below.

If you do not see your AD domain in the list, you can authenticate to Directory Utility by clicking the lock in the lower-left corner, and then add a new search path by clicking the "+" button below the list of paths. Your domain should show up under "Available Directory Domains".

This setting should allow users to authenticate against Active Directory when connecting to your server. However, if AD users can authenticate against your OS X server successfully, the Search Path is not likely to be the culprit.

Alternatively, Workgroup Manager still exists, and may allow you to investigate the AD node more explicitly.

Lastly, you may be required to enable cleartext authentication to be able to authenticate your AD users to your OS X Server hosted wiki (the article applies to Mountain Lion and lower systems, but may be the same procedure that is required for Mavericks).