Plugin doesn´t work after http – https

Hi,
after my changes from http to https the plugin doesn´t work anymore. for example on this page: https://www.fernstudium-bewertung.com/fernstudium-gesundheit-pflege-soziales

After login to the plugin (admin part) I can open every single installed/saved tab, but I can´t see the content of the tab 🙁
any idea?
thank you