[Resuelto] Language is not showing

Background of the issue:
I am trying to fix an issue where languages are mixed on my website. Some pages are displayed in Italian but are listed under Slovenian in the menu. Slovenian is not showing, and when I click on any Italian language link, it redirects to English. Cache is off, and the redirection plugin has been deleted. The issue can be seen on this page: enlace oculto

Symptoms:
Links are not opening as they are supposed to, and I am getting different content in different languages.

Questions:
Why are some pages showing in Italian but listed under Slovenian in the menu?
Why does clicking on Italian language links redirect to English?