diff --git a/src/nginxconfig.ejs b/src/nginxconfig.ejs
index a43a6290a..2c64c90cb 100644
--- a/src/nginxconfig.ejs
+++ b/src/nginxconfig.ejs
@@ -99,7 +99,7 @@ server {
     add_header Content-Security-Policy "default-src 'none'; frame-src 'self' cloudron.io *.cloudron.io; connect-src wss: https: 'self' *.cloudron.io; script-src https: 'self' 'unsafe-inline' 'unsafe-eval'; img-src * data:; style-src https: 'unsafe-inline'; object-src 'none'; font-src https: 'self'; frame-ancestors 'none'; base-uri 'none'; form-action 'self';";
 <% } else { %>
     <% if (frameAncestorsQuoted) { %>
-    add_header Content-Security-Policy "Frame-ancestors  <%= frameAncestorsQuoted %>";
+    add_header Content-Security-Policy "Frame-ancestors  <%- frameAncestorsQuoted %>";
     <% } else { %>
     add_header Content-Security-Policy "Frame-ancestors 'self'";
     <% } %>