Summary excerpt

On my home page I have a summary block for testimonial posts. There should be an excerpt (which is ticked in summary settings) they are invisible. There's a gap where they should be, but no text. And I think it's worth noting that even on the blog page (where I listed my testimonials as posts) the excerpts are not showing. Does maybe someone know what I should do or if it's a bug how to solve it?

For reference this is my homepage: yogamethod.nl