Unable to grant a user with admin priviledges

I have users given prviledges based on user groups and all user all logging in through LDAP auth.
I need to give specific user to have admin privileges. For this under Configure global security i checked the column against “Administrator” so that he can be having admin prviledges to see “manage Jenkins”.
Post user refreshed cached and tried to login the user still unable to see the admin privileges.
In some forum they say i need to do safe restart to reflect. Please confirm if the reflections will happen only post restart of jenkins

Changes should work immediately. Don’t forget to save/apply the changes after granting the permission

Any clue on how to debug more. As post clicked save/apply its not reflecting.

maybe the userid is wrong to which you grant the permission.

No no.The user assigned is the right user. My question is if in LDAP mode we define such that thats not a admin user but in manage credentials i configure that user as admin which will have higher precedence here

with ldap you only authenticate (check if the user exists and to which groups the user belongs).
In the authorization (I assume you’re using matrix auth plugin) you grant permissions to users or groups
This grants admin permission to a user