Are you on an iPhone or iPad? If so, it's probably the default iOS Calendar app. Here are some instructions for adding a calendar to the iOS Calendar:clarkhall wrote:I don’t think it’s Google it is a white box with the day at the top and number in the middle.
https://www.imore.com/how-subscribe-cal ... ne-or-ipad
You will need the sync URL for the calendar. You can skip the User Name, Password, and SSL fields.