You'll see this error when saving a rota if the calendar pattern end date falls outside the supported date range of 01/01/1900 to 06/06/2079. You can resolve this by updating the end date to fall within the supported range.
Resolve the error
Open the rota and locate the calendar pattern with the incorrect end date.
Update the end date so that it falls within the supported date range of 01/01/1900 to 06/06/2079.
Click Save.
đ Note: If you are unsure which calendar pattern is causing the error, check all patterns in the rota for end dates that fall outside the supported range.