apt-get update GPG error: NO_PUBKEY

I recently try to update the package lists on RN214 running ReadyNasOS 6.6.0 version. and got the following error:

root@nas-5D-CF-8E:/etc/apt# apt-get update
Get:1 http://egnyte-cdn.egnyte.com 6.6 InRelease [2,823 B]
Hit http://security.debian.org jessie/updates InRelease
Ign http://mirrors.kernel.org jessie InRelease
Ign http://apt.readynas.com 6.6.0 InRelease
Hit http://mirrors.kernel.org jessie Release.gpg
Ign http://egnyte-cdn.egnyte.com 6.6 InRelease
Ign http://egnyte-cdn.egnyte.com 6.6/egnyte armel Packages/DiffIndex
Ign http://egnyte-cdn.egnyte.com 6.6/egnyte armhf Packages/DiffIndex
Hit http://egnyte-cdn.egnyte.com 6.6/egnyte armel Packages
Ign http://apt.readynas.com 6.6.0 Release.gpg
Hit http://mirrors.kernel.org jessie Release
Hit http://egnyte-cdn.egnyte.com 6.6/egnyte armhf Packages
Hit http://security.debian.org jessie/updates/main armel Packages
Hit http://security.debian.org jessie/updates/main armhf Packages
Hit http://mirrors.kernel.org jessie/main armel Packages
Ign http://apt.readynas.com 6.6.0 Release
Hit http://mirrors.kernel.org jessie/main armhf Packages
Ign http://apt.readynas.com 6.6.0/updates armel Packages/DiffIndex
Ign http://apt.readynas.com 6.6.0/apps armel Packages/DiffIndex
Ign http://apt.readynas.com 6.6.0/main armel Packages/DiffIndex
Ign http://apt.readynas.com 6.6.0/updates armhf Packages/DiffIndex
Ign http://apt.readynas.com 6.6.0/apps armhf Packages/DiffIndex
Ign http://apt.readynas.com 6.6.0/main armhf Packages/DiffIndex
Err http://apt.readynas.com 6.6.0/updates armel Packages
  403  Forbidden [IP: 52.85.144.15 80]
Err http://apt.readynas.com 6.6.0/apps armel Packages
  403  Forbidden [IP: 52.85.144.15 80]
Err http://apt.readynas.com 6.6.0/main armel Packages
  403  Forbidden [IP: 52.85.144.15 80]
Err http://apt.readynas.com 6.6.0/updates armhf Packages
  403  Forbidden [IP: 52.85.144.15 80]
Err http://apt.readynas.com 6.6.0/apps armhf Packages
  403  Forbidden [IP: 52.85.144.15 80]
Err http://apt.readynas.com 6.6.0/main armhf Packages
  403  Forbidden [IP: 52.85.144.15 80]
Fetched 2,823 B in 8s (340 B/s)
W: GPG error: http://egnyte-cdn.egnyte.com 6.6 InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 4ADFF040FC1E91BC
W: Failed to fetch http://apt.readynas.com/packages/readynasos/dists/6.6.0/updates/binary-armel/Packages  403  Forbidden [IP: 52.85.144.15 80]

W: Failed to fetch http://apt.readynas.com/packages/readynasos/dists/6.6.0/apps/binary-armel/Packages  403  Forbidden [IP: 52.85.144.15 80]

W: Failed to fetch http://apt.readynas.com/packages/readynasos/dists/6.6.0/main/binary-armel/Packages  403  Forbidden [IP: 52.85.144.15 80]

W: Failed to fetch http://apt.readynas.com/packages/readynasos/dists/6.6.0/updates/binary-armhf/Packages  403  Forbidden [IP: 52.85.144.15 80]

W: Failed to fetch http://apt.readynas.com/packages/readynasos/dists/6.6.0/apps/binary-armhf/Packages  403  Forbidden [IP: 52.85.144.15 80]

W: Failed to fetch http://apt.readynas.com/packages/readynasos/dists/6.6.0/main/binary-armhf/Packages  403  Forbidden [IP: 52.85.144.15 80]

E: Some index files failed to download. They have been ignored, or old ones used instead.

It seems that apt.readynas.com is NOT working, and egnyte-cdn.egnyte.com requires a GPG pubkey.

Will NETGEAR still allow user to modify/update/install packages from apt.readynas.com? I've searched through the forum and could not find any post regarding this issue.

Thank you for your attention and appreciate any insight on this.

Jim