diff --git a/backend/templates/proxy_host.conf b/backend/templates/proxy_host.conf
index d23ca46fa2..3838bd55ba 100644
--- a/backend/templates/proxy_host.conf
+++ b/backend/templates/proxy_host.conf
@@ -9,6 +9,9 @@ server {
   set $server         "{{ forward_host }}";
   set $port           {{ forward_port }};
 
+  # remove upstream HSTS headers to enforce NPM's HSTS setting and to prevent invalid states (e.g. multiple HSTS headers)
+  proxy_hide_header strict-transport-security;
+
 {% include "_listen.conf" %}
 {% include "_certificates.conf" %}
 {% include "_assets.conf" %}