SDK manager install problem

I am receiving the following error when I am trying to setup my Nvidia Xavier AGX.
I also tried VBox with different version of Ubuntus (16.04 , 18.04) ! yet I have the same problem.
I cannot flash Nvidia Xavier AGX. below you can find the error that I am receiving on sdkm.

SDK Manager is verifying system readiness to install.
Access to APT repository and ability to install Debian packages with it.
Your system is not ready for install, see specific errors below. Once fixed, click ‘Retry’ to verify system readiness again.
Access to APT repository and ability to install Debian packages with it.: Apt repository check failure (sudo -S apt-get update && sudo -S apt-get check).

E: Failed to fetch http://ca.archive.ubuntu.com/ubuntu/dists/bionic-backports/main/binary-arm64/Packages 404 Not Found [IP: 91.189.91.39 80]
E: Some index files failed to download. They have been ignored, or old ones used instead.

Hi aryankia,

The SDK Manager can’t work well on virtual machine, please find the native Ubuntu host machine to run it to flash device.

Thanks