Problem with frontend

At the backend everything joke, but at the frontend I see no date and no possibility to book.

Is there a problem with the theme Serif Lite at http://www.devogelvrij.nl? We also have at http://www.devogelvrij.nl/reserveren/ not one day with the date but it goes on two lines. We are getting crazy of it!

https://ww.wp.xz.cn/plugins/booking-system/