Page not found 404 (big issue)

Hi,

I use this plugin for a few years and it works very good.

But I now encounter a big issue. After duplicating a page, it will be set as a draft. I do now edit the page, but after clicking on ‘Preview’ the page turns 404. So I try to mark the page as ‘Private’, as well not working. Last chance: Publish page, not working.. All 404 page not found.

I always change the permalink/slug of the new duplicate page.

Very strange. Does someone have this same problem?

Thanks!