diff --git a/templates/etc/nginx/conf.d/header.conf.j2 b/templates/etc/nginx/conf.d/header.conf.j2
index 2b76754..a5fec9f 100644
--- a/templates/etc/nginx/conf.d/header.conf.j2
+++ b/templates/etc/nginx/conf.d/header.conf.j2
@@ -1,7 +1,7 @@
 # {{ ansible_managed }}
 # default header settings
 {% if nginx_tls_enabled and nginx_hsts_enabled %}
-add_header Strict-Transport-Security{% if nginx_hsts_options %} "{{ nginx_hsts_options | join("; ") }}{% endif %};
+add_header Strict-Transport-Security{% if nginx_hsts_options is defined %} "{{ nginx_hsts_options | join("; ") }}{% endif %};
 {% endif %}
 add_header X-Frame-Options DENY;
 add_header X-Content-Type-Options nosniff;