ANSWER:

For the sake of completeness you should post your actual mod_authz_ldap configuration directives, not just the log snippets. For me this sounds like a DNS problem somewhere between Apache and AD, but without more info I can’t be sure.

You should try to do the authentication manually using, for example, ldapsearch on the CentOS machine and see if you can reproduce the problem there. Something like:

ldapsearch -xLLLZ -D sAMAccountName=myLdapUSer,dc=mycompany,dc=com -W 
 -b dc=mycompany,dc=com -H ldap://10.10.10.11

by daff from http://serverfault.com/questions/382531