我有一个域名（https://www.maltemafrica.com）和另一个（https://academy.maltemafrica.com/） 直到今天，这两个域都可以正常工作两个月，现在不再安全。
我的Web服务器运行的操作系统是：Ubuntu
我的托管服务提供商是：DigitalOcean
我的certbot版本是0.28.0
我运行了以下命令：certbot renew --dry-run
它产生了以下输出：
Attempting to renew cert (academy.maltemafrica.com) from /etc/letsencrypt/renewal/academy.maltemafrica.com.conf produced an unexpected error: Requesting acme-staging-v02.api.letsencrypt.org/directory: Network is unreachable. Skipping.
我运行了以下命令：curl -v https://acme-staging-v02.api.letsencrypt.org/directory
它产生了以下输出：
Trying 23.75.3.165…
TCP_NODELAY set
Connected to acme-staging-v02.api.letsencrypt.org (23.75.3.165) port 443 (#0)
ALPN, offering h2
ALPN, offering http/1.1
successfully set certificate verify locations:
CAfile: /etc/ssl/certs/ca-certificates.crt
CApath: /etc/ssl/certs
TLSv1.2 (OUT), TLS handshake, Client hello (1):
TLSv1.2 (IN), TLS handshake, Server hello (2):
TLSv1.2 (IN), TLS handshake, Certificate (11):
TLSv1.2 (IN), TLS handshake, Server key exchange (12):
TLSv1.2 (IN), TLS handshake, Server finished (14):
TLSv1.2 (OUT), TLS handshake, Client key exchange (16):
TLSv1.2 (OUT), TLS change cipher, Client hello (1):
TLSv1.2 (OUT), TLS handshake, Finished (20):
TLSv1.2 (IN), TLS handshake, Finished (20):