The calendar of the "Course start date" when restoring a course is transparent

When restoring a course in Moodlecloud, (using Moodle 4.1.1), the calendar to choose a Course start date is transparent. When you want to go forward or backwards by clicking the arrows, you click on the link beneath them, Appearance or Courses in this example (image attached).

The Course start date can be changed by the scroll controls for day, month and year but not by the calendar view.