diff --git a/engine/responder.go b/engine/responder.go
index 747808653..e6da85398 100644
--- a/engine/responder.go
+++ b/engine/responder.go
@@ -329,7 +329,7 @@ func (rs *Responder) GetMaxSessionTime(arg *CallDescriptorWithAPIOpts, reply *ti
 	if arg.Tenant == utils.EmptyString {
 		arg.Tenant = config.CgrConfig().GeneralCfg().DefaultTenant
 	}
-	if arg.Subject == "" {
+	if arg.Subject == utils.EmptyString {
 		arg.Subject = arg.Account
 	}
 	if !rs.usageAllowed(arg.ToR, arg.GetDuration()) {
diff --git a/sessions/sessions.go b/sessions/sessions.go
index 528f9863e..ba959f584 100644
--- a/sessions/sessions.go
+++ b/sessions/sessions.go
@@ -1929,10 +1929,10 @@ func (sS *SessionS) BiRPCv1AuthorizeEvent(clnt rpcclient.ClientConnector,
 		return utils.NewErrMandatoryIeMissing(utils.CGREventString)
 	}
 	var withErrors bool
-	if args.CGREvent.ID == "" {
+	if args.CGREvent.ID == utils.EmptyString {
 		args.CGREvent.ID = utils.GenUUID()
 	}
-	if args.CGREvent.Tenant == "" {
+	if args.CGREvent.Tenant == utils.EmptyString {
 		args.CGREvent.Tenant = sS.cgrCfg.GeneralCfg().DefaultTenant
 	}