Related Posts Module empty in the category page

As you can see here https://www.marketingstudilegali.it/interviste-ad-avvocati
in the right hand column with the title of the form called:
"Forse potrebbero interessarti anche questi articoli"
there are no "recommended" articles but if I go into a post then I see them, how do I solve the problem?

thanks a lot

stefano