404 error after changing wp-admin

Hi
Working with iThemes Security was over a couple of weeks great.
Two days ago I changed the wp-admin login within the plugin of iThemes Security and – so silly – I hadn’t stored the new url-name. When I try to open my website http://www.lemmoney.info, everything works fine. When I try to open …/wp-admin or …/admin, I always get a 404 error. I am unable to login to my dashboard.
I restored all the WP-programs from my last backup previous to the admin-change which worked perfectly, but I discovered the same situation: access to dashboard denied by 404 error.
When I am looking to .htaccess I wonder to find no code which refers to admin login. The content of my .htaccess-file consists of three sections. 1) Ban Users, 2) Tweaks, both being part of my iThemes Security plugin, and 3) WP with some rewrite rules. When I deleted the whole .htaccess nothing worked at all. When I reinstalled the WP-section, the website worked again, but not the dashboard.
Searching via google and searching the posts, I couldn’t find a solution yet.
Please help. Many thanks in advance.
Carlo

https://wordpress.org/plugins/better-wp-security/