This issue can be fixed easily by saving Permalinks in the WordPress Settings > General > Permalinks
Please follow the instructions laid below: https://docs.elementor.com/article/56-content-area-not-found
Regardless of what page builder you use, it can be used together with Elementor. You can keep both Elementor and your preferred builder active at the same time. Use the Shortcode Desginer document to start building your first custom shortcode: https://webnus.net/dox/modern-events-calendar/mec-shortcode-designer-addon/
Once you’ve created your shortcode, copy the shortcode ID for it and paste it in the main page builder you use.
Yes, you can use this addon with MEC Lite as well.
Let me know if you have any other questions in the comment area.