diff --git a/main.go b/main.go
index 6641958..c989dfe 100644
--- a/main.go
+++ b/main.go
@@ -245,7 +245,7 @@ func Main(config *Config, configTest bool, buildVersion string, logger *logrus.L
 	amLighthouse := config.GetBool("lighthouse.am_lighthouse", false)
 
 	// fatal if am_lighthouse is enabled but we are using an ephemeral port
-	if amLighthouse && port == 0 {
+	if amLighthouse && (config.GetInt("listen.port", 0) == 0) {
 		return nil, NewContextualError("lighthouse.am_lighthouse enabled on node but no port number is set in config", nil, err)
 	}