Can't Adjust Thumbnails Size

The page is https://soos-oio.com/updates/

Maybe the plugin has no permission to overwrite the file with the styles. Please on your server in the folder of that plugin set the file ‘public.css’ to writeable.

I went to the folder of recent-posts-widget-with-plugin and there was no public.css file. Is it suppose to be there but missing?

The file seems to be available. The request is valid: https://soos-oio.com/wp-content/plugins/recent-posts-widget-with-thumbnails/public.css

I refreshed the file manager and I found it. Changing the permissions didn’t have any effect. I changed the css directly. Is there any other way that the size can be changed in the plugin rather than going to the css file direct?

Yes, changing the size in the widget form is the way. I don’t know why it does not work on your server.