[Help Wordpress] I can't seem to add new slides

I can't seem to add new slides

I have had RoyalSlider running on my site for quite a while. Today, I tried to add new slides to the slider. But, they won't show up. The ones that have been on there for months still show up. But, when it gets to the new images, all I see is a spinner (as if it is trying to load the image). After a few seconds, it moves onto the next slide, never showing the one I just added.

If I just put the new image URL into a browser, I can see the image fine. The server is finding it. But, Royal Slider isn't.

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help.dimsemenov.com