Category option not working

Hello, I just installed the plugin and the category option is not working. I tried using “cat” and “cats” with various categories, and in all cases the full event list displays. This is the format I’m using:

[ecs-list-events cat=’featured’]

I double checked my slugs and they are correct, and there are no smart quotes or odd characters in the shortcode. Other options are working properly. Any ideas?

https://ww.wp.xz.cn/plugins/the-events-calendar-shortcode/