diff --git a/messages/cs-CZ.json b/messages/cs-CZ.json
index c3286df51..d0d89f12d 100644
--- a/messages/cs-CZ.json
+++ b/messages/cs-CZ.json
@@ -2717,6 +2717,7 @@
     "healthScheme": "Způsob",
     "healthSelectScheme": "Vybrat metodu",
     "healthCheckPortInvalid": "Port musí být mezi 1 a 65535",
+    "healthCheckHostnameInvalid": "Hostname must not contain whitespace",
     "healthCheckPath": "Cesta",
     "healthHostname": "IP / Hostitel",
     "healthPort": "Přístav",