So I'm trying to create a new layer from the following REST service: Layer: Parcel Annotations (ID: 0)
When I try to add this layer through My Content > + Add Item > From the Web
I am getting this error
That URL doesn't even exist... I'm so confused?!
I don't know for sure, and didn't do a thorough search, but could it be that annotation isn't supported?
Add items—ArcGIS Online Help | ArcGIS
I would test to see if one of the other items from the MapServer will work, maybe the Historical Parcels which may not have too many items.