Hello i’m running a rpi with a 3 apps in total. I usually putty into my machine and do yunohost tools update && yunohost tools upgrade. But this time i cannot update anymore :(. If i do a sudo apt update this is what i get:
What does it mean and can i get it working again?
thanks in advance.
W: GPG error: http://deb.debian.org/debian stretch Release: The following signatures couldn’t be verified because the public key is not available: NO_PUBKEY 8B48AD6246925553 NO_PUBKEY 7638D0442B90D010 NO_PUBKEY EF0F382A1A7B6500
E: The repository ‘http://deb.debian.org/debian stretch Release’ 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.