diff --git a/src/components/probe/prober/http/request.ts b/src/components/probe/prober/http/request.ts
index cd9217a0a..89ba4797a 100644
--- a/src/components/probe/prober/http/request.ts
+++ b/src/components/probe/prober/http/request.ts
@@ -587,6 +587,14 @@ function getErrorStatusWithExplanation(error: unknown): {
       }
     }
 
+    case 'CERT_HAS_EXPIRED': {
+      return {
+        status: 18,
+        description:
+          "CERT_HAS_EXPIRED: The website's SSL/TLS certificates has expired.",
+      }
+    }
+
     case 'UNABLE_TO_VERIFY_LEAF_SIGNATURE': {
       return {
         status: 27,