Collaborative playlist, why can't my friend see it and add to it?

[aquaetoile]

Can anyone tell me  how to make a collaborative playlist visible to a fellow spotify subscriber? I make playlists for a radio show, but my co-host makes it with me, so we have been trying to build it together. We have managed in recent weeks, but this week nothing works.  My playlist isn't visible to her or hers to me. If we make them public, then we can't edit or add to them. Does anyone have any suggestions? If we share them in messenger, the same thing applies, we cannot edit it. Thanks.

[thehyenas]

I can see my friend's collaborative music in my playlist, which I'm following, but I cannot add to it - it does not appear in my list when I click "add to playlist"