diff --git a/source/_addons/nginx_proxy.markdown b/source/_addons/nginx_proxy.markdown
index 4bf6c3ad9af..b0e29ece559 100644
--- a/source/_addons/nginx_proxy.markdown
+++ b/source/_addons/nginx_proxy.markdown
@@ -41,8 +41,8 @@ keyfile:
   required: true
   type: string
 hsts:
-  description: Value for the [`Strict-Transport-Security`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Strict-Transport-Security) HTTP header to send. If empty or `null`, the header is not sent.
-  required: false
+  description: Value for the [`Strict-Transport-Security`](https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Strict-Transport-Security) HTTP header to send. If empty, the header is not sent.
+  required: true
   type: string
 customize:
   description: If true, additional NGINX configuration files for the default server and additional servers are read from files in the `/share` directory specified by the `default` and `servers` variables.