Clone Items throwing HTTP error for Feature Layers

deleted-user-7SLqM7dlvYNN

I'm trying to move items between two on premise 10.5.1 Portals and I'm getting an HTTP error when trying to clone a Feature Layer, or Web Maps which reference a Feature Layer. The same code works fine for Web Maps which don't reference feature layers. 

Specific error is: 

Error cloning data:  ('Failed to create Feature Service p18146_Vegetation_Consents: HTTPError: this service url encountered an HTTP Error: http/fullyqualifieddomainname/arcgis/rest/services/Hosted/p18146_Vegetation_Consents/FeatureServer', <Item title:"p18146_AUP_Global_Vegetation_Consents" type:Feature Layer Collection owner:xyz>)

I'm using v1.4.2 of the API and both the source and target server urls are defined as https://

Thanks

Anonymous User

In case anyone else strikes this, the API seems to revert to http if Portal isn't set to only allow for HTTPS connections in the Portal's Security settings (you need to be an admin to have access). As soon as this was changed the error disappeared and the clone function worked going between two 10.6.1 Portals