diff --git a/HowtoOpenSMTPD.md b/HowtoOpenSMTPD.md
index 0fc30935..007fb5bb 100644
--- a/HowtoOpenSMTPD.md
+++ b/HowtoOpenSMTPD.md
@@ -1,5 +1,5 @@
 ---
-categories: OpenBSD email
+categories: openbsd email
 title: Howto OpenSMTPD
 ...