diff --git a/plugin/forward/setup.go b/plugin/forward/setup.go
index cf65c1ba4..8070369c9 100644
--- a/plugin/forward/setup.go
+++ b/plugin/forward/setup.go
@@ -34,7 +34,7 @@ func setup(c *caddy.Controller) error {
 	})
 
 	c.OnStartup(func() error {
-		metrics.MustRegister(c, RequestCount, RcodeCount, RequestDuration, HealthcheckFailureCount, SocketGauge)
+		metrics.MustRegister(c, RequestCount, RcodeCount, RequestDuration, HealthcheckFailureCount, SocketGauge, MaxConcurrentRejectCount)
 		return f.OnStartup()
 	})