Publishing not possible after upgrading

CMS Version

4.4.0

Installation Method

Custom install

Operating System

Debian 13

Issue

After the update from 4.1.2 to the newest version of Xibo, no layouts can be published.

Via Layout section/menu and the context menu, but also, via calendar, I can’t publish a layout.

The error message if I want to preview a layout shows: Error: Invalid, see screenshot.

Already published layouts are still working/showing on the screen. The player on the screen is Tizen, newest version.

Kind regards

Christian