Err:1 https://packages.sury.org/php bullseye InRelease
Certificate verification failed: The certificate is NOT trusted. The certificate issuer is unknown. Could not handshake: Error in the certificate verification. [IP: 104.21.18.148 443]
Hit:2 http://security.debian.org/debian-security bullseye-security InRelease
Hit:3 http://deb.debian.org/debian bullseye InRelease
Hit:4 http://deb.debian.org/debian bullseye-updates InRelease
Reading package lists... Done
W: https://packages.sury.org/php/dists/bullseye/InRelease: No system certificates available. Try installing ca-certificates.
W: Failed to fetch https://packages.sury.org/php/dists/bullseye/InRelease Certificate verification failed: The certificate is NOT trusted. The certificate issuer is unknown. Could not handshake: Error in the certificate verification. [IP: 104.21.18.148 443]
W: Some index files failed to download. They have been ignored, or old ones used instead.
我尝试在 Debian 服务器上安装 PHP 8.0，更新时出现此错误，我该如何删除它。