I recently changed the managed database for my ArcGIS Server instance federated with Portal for ArcGIS, and configured as a hosting server, to an ArcGIS Data Store. Now when I try to publish a hosted service in Portal I get the error "Publish exception ' Exception: Connection reset'". Initially, I tried removing ArcGIS Server or un-federating it with Portal, and then adding it again. I also tried different types of data (zipped up shapefiles, csv spreadsheets, etc.) and they all give that error. If I take that same data and publish to that instance of ArcGIS Server through ArcMap, that works fine. So it seems that there is some connection error between Portal and Server that I can't figure out. Both my Server and Portal are at version 10.3.