sky@DESKTOP-IU948AR:~$ sudo apt update [sudo] password for sky: Err:1 https://security.debian.org/debian-security bookworm-security InRelease Certificate verification failed: The certificate is NOT trusted. The certificate issuer is unknown. Could not handshake: Error in the certificate verification. [IP: 151.101.2.132 443] Err:2 https://mirrors.tuna.tsinghua.edu.cn/debian bookworm InRelease Certificate verification failed: The certificate is NOT trusted. The certificate issuer is unknown. Could not handshake: Error in the certificate verification. [IP: 101.6.15.130 443] Err:3 https://mirrors.tuna.tsinghua.edu.cn/debian bookworm-updates InRelease Certificate verification failed: The certificate is NOT trusted. The certificate issuer is unknown. Could not handshake: Error in the certificate verification. [IP: 101.6.15.130 443] Err:4 https://mirrors.tuna.tsinghua.edu.cn/debian bookworm-backports InRelease Certificate verification failed: The certificate is NOT trusted. The certificate issuer is unknown. Could not handshake: Error in the certificate verification. [IP: 101.6.15.130 443] Reading package lists... Done Building dependency tree... Done Reading state information... Done All packages are up to date. W: https://mirrors.tuna.tsinghua.edu.cn/debian/dists/bookworm/InRelease: No system certificates available. Try installing ca-certificates. W: https://security.debian.org/debian-security/dists/bookworm-security/InRelease: No system certificates available. Try installing ca-certificates. W: https://mirrors.tuna.tsinghua.edu.cn/debian/dists/bookworm-updates/InRelease: No system certificates available. Try installing ca-certificates. W: https://mirrors.tuna.tsinghua.edu.cn/debian/dists/bookworm-backports/InRelease: No system certificates available. Try installing ca-certificates. W: Failed to fetch https://mirrors.tuna.tsinghua.edu.cn/debian/dists/bookworm/InRelease Certificate verification failed: The certificate is NOT trusted. The certificate issuer is unknown. Could not handshake: Error in the certificate verification. [IP: 101.6.15.130 443] W: Failed to fetch https://mirrors.tuna.tsinghua.edu.cn/debian/dists/bookworm-updates/InRelease Certificate verification failed: The certificate is NOT trusted. The certificate issuer is unknown. Could not handshake: Error in the certificate verification. [IP: 101.6.15.130 443] W: Failed to fetch https://mirrors.tuna.tsinghua.edu.cn/debian/dists/bookworm-backports/InRelease Certificate verification failed: The certificate is NOT trusted. The certificate issuer is unknown. Could not handshake: Error in the certificate verification. [IP: 101.6.15.130 443] W: Failed to fetch https://security.debian.org/debian-security/dists/bookworm-security/InRelease Certificate verification failed: The certificate is NOT trusted. The certificate issuer is unknown. Could not handshake: Error in the certificate verification. [IP: 151.101.2.132 443] W: Some index files failed to download. They have been ignored, or old ones used instead.
sky@DESKTOP-IU948AR:~$ sudo apt install ca-certificates Reading package lists... Done Building dependency tree... Done Reading state information... Done Package ca-certificates is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source
E: Package 'ca-certificates' has no installation candidate