Hi @Samuele Provvedi ,
To troubleshoot this issue, we'd need more information about exactly what errors you are getting. I would suggest first by collecting logs and reviewing them to see if it provides you with any clues to your issue. The most common reason I have seen image downloads fail is because of firewalls blocking access to some endpoint, but there are certainly other reasons as well. If you are unable to determine the issue from the logs, I would recommend opening a support request to troubleshoot the issue further.
Hope this helps!