How To Disable Signin restrictions On Gitlab Server
How To Disable Signin, If you want to only user should be authenticate from AD Server, So you can disable the Sign-in on the Gitlab Server.
Check Out : Disable Sign-UP On Gitlab
You need to login with Admin user and follow the below steps
Click on Settings And look for Sign-in Restriction
Click on Expand and unchecked both Password Authentication.
Check Out : Change Gitlab IP URL With Hostname
Save settings and go back to your login page you will see only LDAP authentication will be there
YouTube Link : Disable Sign in Gitlab