Get:1 http://kali.koyanet.lv/kali kali-rolling InRelease [30.5 kB]
Get:2 https://packages.microsoft.com/repos/microsoft-debian-stretch-prod stretch InRelease [4009 B]
Get: 3 http://kali.koyanet.lv/kali kali-rolling/main armhf Packages [17.4 MB]
Err:2 https://packages.microsoft.com/repos/microsoft-debian-stretch-prod stretch InRelease
The following signatures couldn't be verified because the public key is not available: NO_PUBKEY EB3E94ADBE1229CF
Get:4 http://kali.koyanet.lv/kali kali-rolling/contrib armhf Packages [85.8 kB]
Get:5 http://kali.koyanet.lv/kali kali-rolling/non-free armhf Packages [135 kB]
Reading package lists… Done
W: GPG error: https://packages.microsoft.com/repos/microsoft-debian-stretch-prod stretch InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY EB3E94ADBE1229CF
E: The repository ' https://packages.microsoft.com/repos/microsoft-debian-stretch-prod stretch InRelease' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.