diff --git a/internal/service/node.go b/internal/service/node.go
index a3a0f97..c6d3f73 100644
--- a/internal/service/node.go
+++ b/internal/service/node.go
@@ -377,7 +377,8 @@ func serverKey(createdAt *time.Time, size int) string {
 
 	// Match XBoard's Helper::getServerKey(created_at, size):
 	// base64_encode(substr(md5($timestamp), 0, size))
-	sum := md5.Sum([]byte(createdAt.Format("2006-01-02 15:04:05")))
+	// In XBoard, created_at is cast to a Unix timestamp before md5().
+	sum := md5.Sum([]byte(strconv.FormatInt(createdAt.Unix(), 10)))
 	hex := fmt.Sprintf("%x", sum)
 	if size > len(hex) {
 		size = len(hex)