Q: iMac not syncing contacts or calendar

Has anyone else had issues with your iMac not syncing your contacts or calendar? I can edit a contact on either iCloud.com, my iPhone, or my iPad and it will sync with all the devices, including the iMac. However, if I add an event on the calendar on the iMac or add/edit a contact in Contacts on the iMac it DOES NOT sync to the rest of the formats. It is very frustrating. Any ideas on what the issue is?