Since my add-in is not yet officially listed in Microsoft AppSource I don't have a link to the add-in in MS AppSource. But as long as my link (currently points to https://store.office.com) does not link to the correct target, the MS test team won't accept my add-in. :(
So, I somehow need to have the chance to look into the future or is there another way? I assume so, otherwise it would be a never-ending story ;)