一、经确认是SSL证书过期了，但是安装以后出现问题：Unable to find a virtual host listening on port 80 which is currently needed for Certbot to prove t o the CA that you control your domain. Please add a virtual host for port 80.
这个模式会让 Certbot 自己启动一个临时的、独立的 Web 服务器来占用80端口完成验证。这需要你暂时停止正在运行的主 Web 服务（比如 Nginx 或 Apache），因为80端口同一时间只能被一个程序占用
操作步骤：
bash
sudo systemctl stop apache2
sudo certbot certonly --standalone -d www.xxxxx.com
sudo systemctl start apache2二、自动续期出现问题：Failed to renew certificate www.bioseqdata.com with error: Could not bind TCP port 80 because it is already in use by another process on this system (such as a web server). Please stop the program in question and then try again.
三、最后一招
