diff --git a/cmd/cgr-engine/cgr-engine.go b/cmd/cgr-engine/cgr-engine.go
index c371d2ff0..b28dadb6a 100644
--- a/cmd/cgr-engine/cgr-engine.go
+++ b/cmd/cgr-engine/cgr-engine.go
@@ -268,9 +268,13 @@ func checkConfigSanity() error {
 		return errors.New("SessionManager on Worker")
 	}
 	if cfg.BalancerEnabled && cfg.RaterEnabled && cfg.RaterBalancer != DISABLED {
-		engine.Logger.Crit("The balancer is enabled so it cannot connect to another balancer (change [engine]/balancer to disabled)!")
+		engine.Logger.Crit("The balancer is enabled so it cannot connect to another balancer (change rater/balancer to disabled)!")
 		return errors.New("Improperly configured balancer")
 	}
+	if cfg.CDRSEnabled && (cfg.CDRSMediator == INTERNAL && !cfg.BalancerEnabled) {
+		engine.Logger.Crit("CDRS cannot connect to mediator. Enable it first!")
+		return errors.New("Internal Mediator required by CDRS")
+	}
 	if cfg.HistoryServerEnabled && cfg.HistoryServer == INTERNAL && !cfg.HistoryServerEnabled {
 		engine.Logger.Crit("The history agent is enabled and internal and history server is disabled!")
 		return errors.New("Improperly configured history service")