Change permalink structure from ‘Plain’ to ‘Post name’ – plugin doesnt work

I created a fresh WordPress install on the site. I changed the permalink structure from ‘Plain’ to ‘Post name’.

I installed the change wp-admin login plugin.

I added ‘atticus-login’ as the login url. I left the redirect url blank.

I cannot log into the website using:

http://www.toyotetsudatasettlement.com/wp-admin

or

http://www.toyotetsudatasettlement.com/?atticus-login

I have used this plugin multiple times, but have always left the permalink structure as ‘Plain’. Does the plugin work with all permalink structures? If so, what am I doing wrong?