Set user ROLE_ADMIN when using pre-auth

Problem:
Hi, all.
I’m trying to run horizon behind the Nginx with pre-authentication. After configuring according to the pre-authentication doc, the user who has the ROLE_USER can log in successfully. However, the user with role ROLE_ADMIN will get the 403 access denied after logging in. I wonder if it is expected for the user who has role ROLE_ADMIN cannot log in through pre-auth or if I have missed some configuration?

Also, I cannot find pre-auth user in user list(/opennms/admin/userGroupView/users/list.jsp), I wonder if it is excepted.

Thanks a lot.

OpenNMS version:
opennms/horizon:30.0.2

Only local users (that exist in users.xml) are displayed.