@AngeAlexGIS -- Is the story that you are trying to add published? Draft stories cannot be added to a collection. If the story is owned by someone outside your organization, you'll need to favorite it first, then you'll be able to add it to a collection.
Hi @oevans_storymaps - yes, the story has been published and it is owned by our org. This has been an issue for some months now. I had to recreate one of my collections a few months ago to add another story map to it. I hope we can find a solution to this soon.
@AngeAlexGIS -- Just to confirm, how are you searching for your story and who owns it? Are you able to see it when searching your organization on ArcGIS.com? After you click "Add to collection" can you make sure the "My Organization" tab is active and try searching by the story ID?
@OwenGeo - Yes, I can see it in ArcGIS Online when searching in my org, but I cannot see it when I am trying to "Add to collection" searching for it in my "Org" tab or "My Content" tab. It's really strange. I also tried searching for it by ID but that didn't work.