I have the same problem with WP Posts Carousel plugin v.1.2.3 on my Sydney theme v.1.20.
By the way, sydney theme has some styles for .owl-* objects in it’s style.css file, but I’ve commented all of it. Carousel still not working. The problem definitely not in there.
Then I’ve checked the front-end side of my website:
– Plugin’s owl.carousel.css and carousel’s template stylesheets and owl.carousel.js scrypt are loaded, html <script> with load() function of carousel’s parameter’s has its place just after carousel itself. I think just like it should be
– jquery.js v.1.11.3 and jquery.mousewheel.min.js v.3.1.12 libraries are loaded correctly as well
– html of carousel has a structure, containes all posts information that is expected (e.g. there are 2 “owl-item” divs with title,description etc.). But it is hidden!
So, what I’ve found is that #wp-post-carousel div does not have the “owl-loaded” class. Adding this class makes “wp-posts-carousel-slide” elements visible with all containing posts and meta data as well.
It makes me think that for some reason when loading of this carousel is finished, some usefull event doesn’t trigger or makes it incorrectly.
I hope, this information could be usefull fo catching the problem
My test page with WP posts Carousel is here: https://svetlanasima.ru/989-2/