Added to ulr pages /index.php

Hi,

I have already installed Polylang in 2 other sites, following the same procedure, in this in the ulr of each page /index.php has been added:
https://accademia.percorsimpi.com/perseo/index.php/home-ita/

It should be
https://accademia.percorsimpi.com/perseo/home-ita/
Permalink management is always the same.
Polylng options are the same!

Do you have any useful advice?

Thank you`

The page I need help with: [log in to see the link]