I had to adjust the assignment settings after there were submissions. Now I am unable to post the grades by making them visible in Speed Grader. When I click on the EYE icon, this alert comes up. 

When I go into GRADEBOOK and try to release the grades, the option for posting grades is grayed out and not responsive. 

Has anyone had the same problem? Any ideas on why this is happening or how it can be resolved?  Thank you in advance!