Leaflet Maps Maker don’t show map

Good morning,
I am using the Leaflet Maps Marker plugin on the site https://www.educazionestradalelombardia.it/ which displays at the home page, it happens that if the page is viewed by a logged in user it can be seen, while for visitors it is not displayed.
Why does this happen?
I specify that I use OpenStreetMap

Thanks

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