Are you sure error

Currently trying to solve the same error.

Latest version of wordpress is not listed as supported for this plugin.

Ahh, that is probably the issue. Bummer ?? Hopefully the developers get it fixed soon. I would have loved to use the feature.

same problem, the latest updates took away the functionality.

If you’re also using Time.ly’s All-In-One Event Calendar, it is the culprit. Time.ly, despite having paying users, won’t fix it, though (see here if interested in that).

You can find the solution to the issue here: https://www.ads-software.com/support/topic/clone-and-new-post-not-working/#post-6518664