Shared calendar not syncing to all devices

My husband has shared a calendar with me. I received the invite e-mail to join his calendar on my MacBook Air. When I clicked the Join Calendar button, it opened iCloud.com, had me sign in and the calendars appeared there. They are also showing on my iPhone and iPad; however, they are not showing on my MacBook Air (which is, of course, the place I most need to access them. Not sure what setting is not correct. Any help would be appreciated. Thanks!