At the end of a semester, your grades must be submitted in iStar; they do not automatically transfer from D2L. Your students will not get credit for the course if you do not transfer the grades manually. See Submit iStar grades for instructions on how to enter your grades in iStar. (You will have to log in to view the link.)
If you encounter difficulties while entering your grades into iStar, you can contact the IT office either through their chat service (at the bottom of the page) or via phone support at 866-614-5014. You may also want to talk to your DOM or DOS about the problems you are having with entering your grades in iStar.