diff --git a/src/lang/en.json b/src/lang/en.json
index 8b74eb5ef..72a51fdd9 100644
--- a/src/lang/en.json
+++ b/src/lang/en.json
@@ -1296,6 +1296,7 @@
     "labelDomainNameExpiryNotification": "Domain Name Expiry Notification",
     "domainExpiryDescription": "Trigger notification when domain names expires in:",
     "domain_expiry_unsupported_monitor_type": "Domain expiry monitoring is not supported for this monitor type",
+    "domain_expiry_unsupported_invalid_domain": "The configured value \"{hostname}\" is not a valid domain name",
     "domain_expiry_public_suffix_too_short": "\".{publicSuffix}\" is too short for a top level domain",
     "domain_expiry_unsupported_is_icann": "The domain \"{domain}\" is not a candidate for domain expiry monitoring",
     "domain_expiry_unsupported_is_ip": "\"{hostname}\" is an IP address. Domain expiry monitoring requires a domain name",