Ubuntu 22.04下配置Nginx与Certbot安装SSL证书后网站无法访问，Nginx启动失败求助

各位大佬好，我是Ubuntu新手，最近在一台公有虚拟机上搭环境，刚装了Ubuntu 22.04、Nginx和Certbot。之前网站已经能指向我的域名正常访问了，但装完Certbot配置SSL之后彻底崩了——现在不管用HTTP还是HTTPS都打不开网站，Nginx还启动失败了！

我用notmydomain.com作为示例域名，给大家详细说下情况：

按照Certbot官网指引操作后，我执行启动Nginx的命令：

systemctl start nginx.service

结果直接报错：

Job for nginx.service failed because the control process exited with error code.
See "systemctl status nginx.service" and "journalctl -xeu nginx.service" for details.

于是我查了Nginx的状态：

systemctl status nginx.service

输出如下：

× nginx.service - A high performance web server and a reverse proxy server
Loaded: loaded (/lib/systemd/system/nginx.service; enabled; vendor preset: enabled)
Active: failed (Result: exit-code) since Mon 2023-10-30 09:17:39 CDT; 5s ago
Docs: man:nginx(8)
Process: 535771 ExecStartPre=/usr/sbin/nginx -t -q -g daemon on; master_process on; (code=exited, status=1/FAILURE)
CPU: 12ms

systemd[1]: Starting A high performance web server and a reverse proxy server...
nginx[535771]: nginx: [emerg] cannot load certificate key "/etc/letsencrypt/live/notmydomain.com/privkey.pem": PEM_read>
systemd[1]: nginx: configuration file /etc/nginx/nginx.conf test failed
systemd[1]: nginx.service: Control process exited, code=exited, status=1/FAILURE
systemd[1]: nginx.service: Failed with result 'exit-code'.
systemd[1]: Failed to start A high performance web server and a reverse proxy server.

我去检查了证书文件所在目录的权限：

ls -l /etc/letsencrypt/live/notmydomain.com/

输出是：

total 4
lrwxrwxrwx 1 root root  44 Oct 28 03:00 cert.pem -> ../../archive/notmydomain.com/cert1.pem
lrwxrwxrwx 1 root root  45 Oct 28 03:00 chain.pem -> ../../archive/notmydomain.com/chain1.pem
lrwxrwxrwx 1 root root  49 Oct 28 03:00 fullchain.pem -> ../../notmydomain.com/fullchain1.pem
lrwxrwxrwx 1 root root  47 Oct 28 03:00 privkey.pem -> ../../archive/notmydomain.com/privkey1.pem
-rw-r--r-- 1 root root 692 Oct 28 03:00 README

我注意到这些文件都是root用户所有，会不会是Nginx没有权限访问这些证书？这会不会是问题所在？这些证书文件应该改成哪个用户所有才能让Nginx正常访问呢？

另外我也检查了防火墙设置，确保没把自己拦在外面：

ufw status numbered

输出是：

Status: active

To                         Action      From
--                         ------      ----
[ 1] Anywhere                   ALLOW IN    xxx.xxx.xxx.xxx
[ 2] 443/tcp                    ALLOW IN    Anywhere
[ 3] 80/tcp                     ALLOW IN    Anywhere
[ 4] Nginx HTTP                 ALLOW IN    Anywhere
[ 5] Nginx HTTPS                ALLOW IN    Anywhere
[ 6] 443/tcp (v6)               ALLOW IN    Anywhere (v6)
[ 7] 80/tcp (v6)                ALLOW IN    Anywhere (v6)
[ 8] Nginx HTTP (v6)            ALLOW IN    Anywhere (v6)
[ 9] Nginx HTTPS (v6)           ALLOW IN    Anywhere (v6)

我还尝试重新签发了证书，执行过程中没有报错：

certbot certonly --standalone --domain notmydomain.com

输出如下：

Saving debug log to /var/log/letsencrypt/letsencrypt.log
Requesting a certificate for notmydomain.com
Successfully received certificate.
Certificate is saved at: /etc/letsencrypt/live/notmydomain.com-0001/fullchain.pem
Key is saved at:         /etc/letsencrypt/live/notmydomain.com-0001/privkey.pem
This certificate expires on 2024-01-28.
These files will be updated when the certificate renews.
Certbot has set up a scheduled task to automatically renew this certificate in the background.

现在实在不知道该查哪里了，有没有大佬能给点指导？需要更多信息的话我随时提供！

备注：内容来源于stack exchange，提问作者ErocM