数字海洋nginx“有效：失败（结果：退出代码）”

Question

第一次使用数字海洋。我在他们的网站上关注该教程，但遇到了此错误，不知道出了什么问题或如何解决。某些方向将不胜感激。

*** System restart required ***
Last login: Mon Oct  1 17:09:09 2018 from 184.190.9.89
root@fret-finder:~# systemctl status nginx
● nginx.service - A high performance web server and a reverse proxy server
   Loaded: loaded (/lib/systemd/system/nginx.service; enabled; vendor preset: en
   Active: failed (Result: exit-code) since Mon 2018-10-01 17:38:17 UTC; 17min a
     Docs: man:nginx(8)
  Process: 14127 ExecStartPre=/usr/sbin/nginx -t -q -g daemon on; master_process
 Main PID: 13327 (code=killed, signal=KILL)

Oct 01 17:38:17 fret-finder systemd[1]: Starting A high performance web server a
Oct 01 17:38:17 fret-finder nginx[14127]: nginx: [emerg] BIO_new_file("/etc/lets
Oct 01 17:38:17 fret-finder nginx[14127]: nginx: configuration file /etc/nginx/n
Oct 01 17:38:17 fret-finder systemd[1]: nginx.service: Control process exited, c
Oct 01 17:38:17 fret-finder systemd[1]: nginx.service: Failed with result 'exit-
Oct 01 17:38:17 fret-finder systemd[1]: Failed to start A high performance web s
lines 1-13/13 (END)...skipping...
● 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 2018-10-01 17:38:17 UTC; 17min ago
     Docs: man:nginx(8)
  Process: 14127 ExecStartPre=/usr/sbin/nginx -t -q -g daemon on; master_process on; (code=exited, status=1/FAILURE)
 Main PID: 13327 (code=killed, signal=KILL)

Oct 01 17:38:17 fret-finder systemd[1]: Starting A high performance web server and a reverse proxy server...
Oct 01 17:38:17 fret-finder nginx[14127]: nginx: [emerg] BIO_new_file("/etc/letsencrypt/live/fret-finder.com/fullchain.pem") failed (SSL: error:02001002:system lib
Oct 01 17:38:17 fret-finder nginx[14127]: nginx: configuration file /etc/nginx/nginx.conf test failed
Oct 01 17:38:17 fret-finder systemd[1]: nginx.service: Control process exited, code=exited status=1
Oct 01 17:38:17 fret-finder systemd[1]: nginx.service: Failed with result 'exit-code'.
Oct 01 17:38:17 fret-finder systemd[1]: Failed to start A high performance web server and a reverse proxy server.
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