Hello
I tried to do an apt-get update for the first time and this is result. What's happening? Could you help?
Code
Reading package lists... Done
W: GPG error: http://ppa.launchpad.net/kyle1117/ppa/ubuntu cosmic InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 3028C3C96AD57103
W: The repository 'http://ppa.launchpad.net/kyle1117/ppa/ubuntu cosmic InRelease' is not signed.
N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration details.
root@odroidxu4:~#
Thanks in advance!