Can't get captions to show

Hi,
I can’t get captions to show.
My Media Library Gallery Shortcode looks like this:
[gallery ids="9076,8637,9578,8631"]
and displays the default gallery with captions under the thumbnails.

When I activate this plugin, there are no captions.

I modify the shortcode to any of these attempts below, but no captions display.
[gallery ids="9076,8637,9578,8631" captions="on"]
[gallery captions="on" ids="9076,8637,9578,8631" ]
[gallery ids="9076,8637,9578,8631" captions="title"]
[gallery captions="title" ids="9076,8637,9578,8631" ]
[gallery captions="true" ids="9076,8637,9578,8631" ]

Please tell me what I’m doing wrong or did I misunderstand this function.

Thank you.

https://www.ads-software.com/plugins/responsive-gallery-grid/