Problem with Sync from Andoid Calender
I found that the calendar sync does not work when the phone is "full", i.e., far over half of available storage is used by all your downloaded apps, and pictures, documents etc. In my case, I don't remember the exact numbers, but with some 90 % usage, but still say half a gigabyte free, this turned out to be not sufficient for Calendar. I removed some unused apps, and Calendar started syncing again.