The Non-Bookable Rooms widget indicates dates that are not available for bookings because the minimum length of stay is higher than the number of consecutive dates available.

NOTE: This will only be visible on your dashboard if there are MLOS restrictions in place that are causing dates that cannot be booked.

By clicking on the Show in Calendar button, you have the ability to reduce the MLOS for the dates indicated in the dashboard widget if you would like to allow bookings to be made.