diff --git a/config/environments/production.rb b/config/environments/production.rb
index 018de6bc..f4957c11 100644
--- a/config/environments/production.rb
+++ b/config/environments/production.rb
@@ -89,7 +89,7 @@
 
   # Enable DNS rebinding protection and other `Host` header attacks.
   config.hosts = [
-    /service-manual-publisher\..*gov.uk?/,
+    /service-manual-publisher\..*\.gov.uk?/,
   ]
 
   # Skip DNS rebinding protection for the default health check endpoint.