[Решено] Translated post not created

We have problems with our portfolio item grid. We use Enfold as a theme, where we have portfolio items in both Dutch and English. When I go to the portfolio items tab, as seen in the screenshot, and try to add a '+', I see the screen where I can add translations per string, which are prefilled because this site is a copy of another website. When I press save and close, the entry does not save and the '+' sign is still there.