New computer. Calendar entries not appearing on new iMac.

I have an iCloud calendar that I am sharing with two other people. I recently purchased a new computer. New and old computers are side by side (for now). Entries in the iCloud calendar that is shared are not appearing on the new computer's Calendar. If I create a new appointment in this calendar it appears but any entries that existed prior to establishing the account on the new computer don't appear. Refreshing the calendar doesn't do anything now does turning this calendar on/off. Ideas?