Admin access to protect pages

Hi,
I have followed the steps on this page: https://simple-membership-plugin.com/giving-wordpress-admin-user-access-protected-content/

and successfully imported my admin users as members with “Admin Access Level” membership level. Admin Level has access to all content, i can see this on back-end off pages. I have logged out and log in but still cant see a protect content in front-end.

When I am logged in as an admin user and I visit a protected page, I get the protected content message with link to login. If i try to log in there are a message that it is impossible for admin-users.
I deactivated all plugins – it doesnt work. Debug show a message “Script error. line 0” while I try to log-in by the buttum “Join us” while I’m already logged-in like Admin.
Also i allow free membership for admin level ID, it’s also does’t help.

What the problem could be?
Thanks!