There exists a bug in Custom UI macros using the automatic resizing feature, where if an app requires user consent, it will not be visible on the published page. A fix is being actively worked on.
For a workaround, add the viewportSize property to your module to fallback to manual sizing.
Does this also include the behaviour with modal dialogs ?
@FranzBinder I don’t think it does, as this was an issue specifically affecting apps when they display the button to grant user consent. The issue of modals not working in Confluence macros is a separate one that is still in the works.
The fix for this bug has been shipped.