Cannot get cat= shortcode param to work

Hi, I feel like such an idiot for asking a question on what should be a simple action, but I just cannot get it to work.

I’ve got a singular random post box, before it was pulling from all categories, now I want to specify by a singular category (called Blog) but what I’m using for cat is not working as it’s not displaying anything. Please see below –

[arpw limit=”1″ excerpt=”false” excerpt_length=”50″ cat=”Blog”]

What am I doing wrong? Anyone know?

Thanks

https://ww.wp.xz.cn/plugins/advanced-random-posts-widget/