[RobertRegets]

I have also had this issue. Since updating my password due to Heartbleed, I can no longer get OmniFocus tasks with a due date to show up in Calendar. I have tried multiple times to delete the calendar and try again but nothing seems to work. I can see a subscription to the OF calendar appear in the Calendar app, but no tasks ever appear on their respective due dates.

Also, I have experienced the iOS issue where I am prompted to enter my Omni sync credentials over and over again. I am definitely using the correct information because the OF apps sync just fine.

This is very disappointing. I have been using the calendar integration for a while. Sadly, I do not have any suggestions on how to fix this. I have given up trying.