diff --git a/mme/LTE_CryptoFunctions.ttcn b/mme/LTE_CryptoFunctions.ttcn
index dee0f22..9923541 100644
--- a/mme/LTE_CryptoFunctions.ttcn
+++ b/mme/LTE_CryptoFunctions.ttcn
@@ -145,7 +145,7 @@
 					   f_rx_is_downlink(nus), data_with_seq);
 	if (exp_mac != secp_nas.messageAuthenticationCode) {
 		setverdict(fail, "Received NAS MAC ", secp_nas.messageAuthenticationCode,
-			   " doesn't match expected MAC ", exp_mac, ": ", secp_nas);
+			   " doesn't match expected MAC ", exp_mac, ": ", secp_nas, " | nus: ", nus);
 		return false;
 	}
 	return true;