User not able to access from AD account

I am running a Gitlab instance, on the login page 2 kinds of login can be seen AD login and standard login.
On adding a user from Gitlab UI and creating an Identity. The user is not able to login via AD, instead the account works via standard login.
gitlab-rake gitlab:ldap:check[10000] | grep

The user is not found

Any tips on how can this be resolved.