ERROR 2016-01-29 20:46:43,837 [http-9050-366] directory.LDAPDirectoryService (1229616:271099556__-1F21EFBF_1528D4F0D93_7F6F:security.loginAction)
authenticate():Could not talk with the Directory Server.
1) Directory server is down,
2) Machine where Niku appserver is running is not able to communicate with Directory server.
Contact your Directory server administrator.
Please let me know the issue for the above available error in Apps log file.