Unable to download gadget/kernel snaps

Trying to download the kernel and gadge snaps on Dell Edge Gateway 3000 with out success. Is there a restriction on the downloads for these two types (gadget and kernel) ?

$ snap info caracalla
name:      caracalla
summary:   Dell system package for AMD64
publisher: Canonical✓
contact:   snappy-canonical-storeaccount@canonical.com
license:   unset
description: |
  This package contains a simple OEM snappy package for system configuration
commands:
  - caracalla.hibernate-handler
type:         gadget
snap-id:      ttZZbj4ZjaFakobHQghX8Z6C5SOTtK0j
tracking:     stable
refresh-date: 2018-01-29
channels:
  stable:    16.04-1.35 (49) 860kB -
  candidate: 16.04-1.35 (49) 860kB -
  beta:      16.04-1.35 (49) 860kB -
  edge:      16.04-1.37 (51) 864kB -
installed:   16.04-1.35 (49) 860kB gadget

$ snap find caracalla --narrow
Name               Version          Publisher   Notes   Summary
caracalla-iot-nxt  16.04-1.g1.4     dell-inc    gadget  Dell system package for AMD64
caracalla-kernel   4.4.0-135.161-1  canonical✓  kernel  The generic kernel for snappy
caracalla          16.04-1.35       canonical✓  gadget  Dell system package for AMD64


$ snap download caracalla
Fetching snap "caracalla"
error: cannot download snap "caracalla": snap not found

Also , Trying to fetch the revision info of these kernel snap from the snap store on a normal ubuntu 16 machine fails with 404 not found error .Is there something I am missing here ?

$ http --pretty=format --print b https://api.snapcraft.io/v2/snaps/info/caracalla architecture==amd64 fields==architectures,base,confinement,contact,created-at,description,download,epoch,license,name,prices,private,publisher,revision,snap-id,snap-yaml,summary,title,type,version,media,common-ids Snap-Device-Series:16
{
    "error-list": [
        {
            "code": "resource-not-found",
            "message": "No snap named 'caracalla' found in series '16'."
        }
    ]
}

I’ll defer to the Store team on this, but I think you need an Ubuntu SSO account that has at least Viewer role in the Caracalla store. Then you can snapcraft login with that account and generate a credentials file like this:

$ snapcraft export-login --acls package_access creds

Then you could run snap download like this:

$ UBUNTU_STORE_AUTH_DATA_FILENAME=/ABSOLUTE_PATH/creds UBUNTU_STORE_ID=THE_STORE_ID snap download SNAP_NAME

Thanks for the hints, I will give a try and see if that works.