Use only the user name portion of your Tulane email.  jdoe, instead of jdoe@tulane.edu.

If you enter your credentials and nothing happens (i.e. you don't get an error message and you don't get logged in), you probably have a bad cookie.

Google search "how to remove a single cookie" for your browser.  The cookie you want to remove is intranet.law.tulane.edu.