.htaccess bind Apache server to ldap causes Internal server error 500

Question

Using wamp server with apache 2.4.4

I have a directory that I want to protect with .htaccess file:

AuthBasicProvider ldap
AuthType Basic
AuthName "Authentication required "
AuthLDAPUrl "ldap://myldap:389/ou=p1,dc=dt,dc=mycompany,dc=local?uid?sub?(objectClass=*)"

AuthLDAPBindDN "cn=admin,dc=dt,dc=mycompany,dc=local"
AuthLDAPBindPassword "password"
Require valid-user

I have AllowOverride all set in httpd.conf.

I have all LoadModule directives uncommented in httpd.conf

I can successfully create connection to the ldap using Apache Directory Studio using these BindDN and password.

I can also successfully query ldap://myldap:389/ou=p1,dc=dt,dc=mycompany,dc=local?uid?sub?(objectClass=*) using Windows Explorer

EDIT: I get the authentication window as it should be but whatever creditentials I enter I get Internal Server Error 500.

Any suggestions?