D2L requires security to your Internt browser, but not security so tight that you can't send information to D2L.  You will need to adjust the "Cookies" to be Enabled on your Internet browser.

Internet Explorer, choose TOOLS > INTERNET OPTIONS > PRIVACY and set the slider to MEDIUM.

Netscape Navigator, choose TOOLS > OPTIONS > PRIVACY and in the section for Cookies, checkmark both [X] Accept Cookies From Sites, [X] For the Originating Site Only, and then also choose KEEP UNTIL: I CLOSE NAVIGATOR.