ubuntu | 镜像站使用帮助 | 清华大学开源软件镜像站 | Tsinghua Open Source Mirror

临时将更新方式改为http方式

sudo vim/etc/apt/sources.list
# 将其中的 https 暂时改成http
# 退出保存
#重新安装两个组件
apt-get reinstall apt-transport-https ca-certificates

再次修改回HTTPS方式

sudo vim /etc/apt/sources.list

---------------建议修改成为下述内容，为清华镜像站建议的方式，注意你操作系统的版本
# 默认注释了源码镜像以提高 apt update 速度，如有需要可自行取消注释
deb https://mirrors.tuna.tsinghua.edu.cn/debian/ buster main contrib non-free
# deb-src https://mirrors.tuna.tsinghua.edu.cn/debian/ buster main contrib non-free
deb https://mirrors.tuna.tsinghua.edu.cn/debian/ buster-updates main contrib non-free
# deb-src https://mirrors.tuna.tsinghua.edu.cn/debian/ buster-updates main contrib non-free
deb https://mirrors.tuna.tsinghua.edu.cn/debian/ buster-backports main contrib non-free
# deb-src https://mirrors.tuna.tsinghua.edu.cn/debian/ buster-backports main contrib non-free
deb https://mirrors.tuna.tsinghua.edu.cn/debian-security buster/updates main contrib non-free
# deb-src https://mirrors.tuna.tsinghua.edu.cn/debian-security buster/updates main contrib non-free

 参考：debian用清华源出现证书错误解决方法 - 简书