If you are experiencing an issue with your login link not working properly, or refreshing your main page instead of directing you to the login page. This quick work around maybe useful for you.
With most DNN sites, in the browser?s address bar you can append "/?ctl=login" to the end of your domain name and it should take you directly to the default login page. Once logged in again, you can attempt to correct the issue with your login link. An example of this would be if your domain name was "ihostdnn.com" then you would direct your browser to "ihostdnn.com/?ctl=login".