[Risolto] advanced translator environment

Background of the issue:
I am trying to update my translations using the advanced translator environment in WPML. My site (link nascosto) was cloned from another site (kpstudio.gr) and is now on a subdomain.

Symptoms:
When I open the advanced translator environment and click on a segment to translate, it gives me a blank white screen and nothing happens. I have to refresh the page to go back to the advanced translator environment, and I can't update my translations.

Questions:
Why does the advanced translator environment show a blank white screen when I click on a segment to translate?
Could cloning the site to a subdomain be causing this issue?