diff --git a/cmd/thalos/server.go b/cmd/thalos/server.go
index 271452c..72ea05f 100644
--- a/cmd/thalos/server.go
+++ b/cmd/thalos/server.go
@@ -363,6 +363,7 @@ func serverCmd(cmd *cobra.Command, args []string) {
 		s.StartBlock = conf.Ship.StartBlockNum
 		s.EndBlock = conf.Ship.EndBlockNum
 		s.IrreversibleOnly = conf.Ship.IrreversibleOnly
+		s.MaxMessagesInFlight = 1
 	})
 
 	// Get codec