Login and Dashboard pages not loading

I’ve installed this great plugin right after I finished the regular installation of wordpress 4.2.2, since I have to be have access to the blog both, from remote networks as well as my LAN.

The installation of wordpress was performed from a remote network and went very smooth. After installing the plugin, I can easily access the blog itself from both, remote as well as local networks, and the dashboard / login-page from a remote network. However, I can not log in / access the wp-dashboard from the local network. The login page itself does load something, but it’s basically just the login form and the plain text blog title above; as soon as I hit the login button, the page fails to load. And if I try to access wp-admin/ instead of wp-login.php, I get redirected to the page with a remote URL (http://mydomainname.com/wordpress/wp-login.php?redirect_to=http%3A%2F%2F192.168.2.195%2Fwordpress%2Fwp-admin%2F&reauth=1).

Any help would by highly appreciated!
And thanks already for the awesome plugin.

https://wordpress.org/plugins/relative-url/