Facebook preview problems

I’ve just got my site up and running at https://mamameditation.co.uk using the Mantra theme.

The issue I’m having is when I try and share the link on Facebook the preview is coming up with the following text:

A cras tincidunt, is a tellus et. Gravida scel sum sed iaculis, is a nunc non nam. Placerat sed hase llus, purus purus elit.

I have no idea where this is coming from or how I can fix it. Any ideas please?