Random Ads Not Showing If Set Automatically

First of all, thank you for the plugin, I really love it and have been using it for many years.

The problem though, today I try to set Random Ads from Setting page to show in some specific places such as beginning of Post, Middle, and End of post. But if I set Random Ads, then there will be no ads shown. If I set specifically Ads1, or Ads2, and others, it will show up. Only if I set to Random Ads that it will not show up in the post.

I tried insert shortcode manually to one post with <!–RndAds–> and it shows up.

So I don’t understand what is the problem.

Thank you.