nicepage 1.9.1 joomla 3.9.6 Import content from template / Request failed: 500

Export theme from nicepage desktop builder Upload theme to joomla Expected result: theme and menu are installed Actual result: massage the content not imported or in templates -> import content ->...

I followed all steps in your video about how to install a template & content in Joomla. Export, install, making new template default went well. Installing nicepage.zip was oké but I got a failure...