plugin problem image doesn't show

Good morning support.
I try to add the plugin but featured image doesn’t appear?
I read some post inside the support…probably there is some conflict with the theme?
I have two different installation of wordpress in the same directory on server.
Can you take a look please?

here the plugin in function

here the feed

Thank you in advance
M

https://www.ads-software.com/plugins/wp-rss-multi-importer/