Mastodon contact cannot see photo in private post
I defined a privacy group with currently only one Mastodon user. When I post with an image (uploaded with the post), he receives the post, but without the image.
I usually rund a custom channel role (I am aware of and regard the "everybody on the internet" permission for reading posts and media items, for AP/Mastodon compatibility, and I do regulate them via privacy groups). But even after changing channel permissions to standard "private social", he could not see images in re-sent posts, or in a completely new one.
What am I missing...?