Sharing public layer from portal

Anonymous User

I am having some issues with trying to get a public layer to show up from our portal

1. I have published an image service to our server: https://staginggeo.grey.ca/server/rest/services/Public/Airphoto2015/ImageServer
2. Then I went in to our portal and tried to share it publicly: https://staginggeo.grey.ca/portal/home/item.html?id=1a08695276044ef2a8d92c6a4f4551de
3. I collaborated this portal data with our ArcGIS Online Organization: https://grey.maps.arcgis.com/home/item.html?id=1a08695276044ef2a8d92c6a4f4551de
4. I did this to try and share it on our open data site: https://maps.grey.ca/search?sort=name
   
   

I can't get it to show on our open data site despite it showing up in https://hub.arcgis.com/admin/data/items

I can access the layer if I try when I am not logged in, even in incognito mode however several other people cannot.

Should I just be adding the server/rest/services link directly into our AGOL org through add item from web? I like the idea of a collaboration as I don't need to duplicate the item. 

Thanks