I have recorded a video showing the “Preview Could Not Be Loaded” error from Elementor Pro when using the XStore theme. The video also shows that it works without a problem when I switch to the Hello Elementor theme.
You can see the video containing both scenarios on https://youtu.be/uJZjycJvoP8. It is a little less than 4 minutes in total and I have put in on a hidden link on YouTube.
I hope you can help me sorting it out.