Your page source has an error
you have an improper > closing tag
<script> src="https://cdnjs.cloudflare.com/ajax/libs/OwlCarousel2/2.2.1/owl.carousel.js"</script>
it should look like :
<script src="https://cdnjs.cloudflare.com/ajax/libs/OwlCarousel2/2.2.1/owl.carousel.js"</script>
also , you should consider switching to tiny-slider GitHub - ganlanyuan/tiny-slider: Vanilla javascript slider for all purposes.