You should try with ldap_search on the Tuleap host
Something like:
ldap_search -x -h 192.168.x.x -LLL -D cn=administrator,cn=users,dc=xx,dc=corp -W -b dc=xx,dc=corp "sAMAccountName=yourlogin"
and see if it returns anything (that's basically what's Tuleap is doing when you try to login)