diff --git a/en_US/troubleshooting/debug.nginx.md b/en_US/troubleshooting/debug.nginx.md
new file mode 100644
index 00000000..21aceb72
--- /dev/null
+++ b/en_US/troubleshooting/debug.nginx.md
@@ -0,0 +1,15 @@
+# Turn on debug mode in Nginx
+
+To turn on debug mode in Nginx, please update Nginx config file
+`/etc/nginx/conf-enabled/log.conf` (Linux/OpenBSD) or
+`/usr/local/etc/nginx/conf-enabled/log.conf` (FreeBSD), append string `debug`
+in parameter `error_log` like below:
+
+```
+error_log ... debug;
+```
+
+Then restart Nginx service.
+
+Nginx logs detailed debug info to `/var/log/nginx/error.log` (Linux/FreeBSD)
+or `/var/www/logs/error.log` (OpenBSD).
diff --git a/html/debug.nginx.html b/html/debug.nginx.html
new file mode 100644
index 00000000..d431ec30
--- /dev/null
+++ b/html/debug.nginx.html
@@ -0,0 +1,40 @@
+<!DOCTYPE html>
+<html>
+    <head>
+        <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
+        <title>Turn on debug mode in Nginx</title>
+        <link rel="stylesheet" type="text/css" href="./css/markdown.css" />
+    </head>
+    <body>
+
+    <div id="navigation">
+    <a href="https://www.iredmail.org" target="_blank">
+        <img alt="iRedMail web site"
+             src="./images/logo-iredmail.png"
+             style="vertical-align: middle; height: 30px;"
+             />&nbsp;
+        <span>iRedMail</span>
+    </a>
+    &nbsp;&nbsp;//&nbsp;&nbsp;<a href="./index.html">Document Index</a></div><h1 id="turn-on-debug-mode-in-nginx">Turn on debug mode in Nginx</h1>
+<p>To turn on debug mode in Nginx, please update Nginx config file
+<code>/etc/nginx/conf-enabled/log.conf</code> (Linux/OpenBSD) or
+<code>/usr/local/etc/nginx/conf-enabled/log.conf</code> (FreeBSD), append string <code>debug</code>
+in parameter <code>error_log</code> like below:</p>
+<pre><code>error_log ... debug;
+</code></pre>
+
+<p>Then restart Nginx service.</p>
+<p>Nginx logs detailed debug info to <code>/var/log/nginx/error.log</code> (Linux/FreeBSD)
+or <code>/var/www/logs/error.log</code> (OpenBSD).</p><div class="footer">
+    <p style="text-align: center; color: grey;">All documents are available in <a href="https://github.com/iredmail/docs/">GitHub repository</a>, and published under <a href="http://creativecommons.org/licenses/by-nd/3.0/us/" target="_blank">Creative Commons</a> license. You can <a href="https://github.com/iredmail/docs/archive/master.zip">download the latest version</a> for offline reading. If you found something wrong, please do <a href="https://www.iredmail.org/contact.html">contact us</a> to fix it.</p>
+</div>
+<!-- Global site tag (gtag.js) - Google Analytics -->
+<script async src="https://www.googletagmanager.com/gtag/js?id=UA-3293801-21"></script>
+<script>
+  window.dataLayer = window.dataLayer || [];
+  function gtag(){dataLayer.push(arguments);}
+  gtag('js', new Date());
+
+  gtag('config', 'UA-3293801-21');
+</script>
+</body></html>
\ No newline at end of file
diff --git a/html/index.html b/html/index.html
index 66907db9..206cad6c 100644
--- a/html/index.html
+++ b/html/index.html
@@ -230,6 +230,7 @@
 <li><a href="debug.fail2ban.html">Turn on debug logging in Fail2ban</a></li>
 <li><a href="debug.iredapd.html">Turn on debug mode in iRedAPD</a></li>
 <li><a href="debug.mysql.html">Log executed SQL commands in MySQL/MariaDB</a></li>
+<li><a href="debug.nginx.html">Turn on debug mode in Nginx</a></li>
 <li><a href="debug.openldap.html">Turn on debug mode in OpenLDAP</a></li>
 <li><a href="debug.postfix.html">Turn on debug mode in Postfix</a></li>
 <li><a href="debug.roundcubemail.html">Turn on debug mode in Roundcube webmail</a></li>
