diff --git a/src/AsyncTCP.cpp b/src/AsyncTCP.cpp
index e11d9aa..5259400 100644
--- a/src/AsyncTCP.cpp
+++ b/src/AsyncTCP.cpp
@@ -78,7 +78,7 @@ typedef struct {
 
 static xQueueHandle _async_queue;
 static TaskHandle_t _async_service_task_handle = NULL;
-const int _number_of_closed_slots = 16;
+const int _number_of_closed_slots = CONFIG_LWIP_MAX_ACTIVE_TCP;
 static int _closed_index = 0;
 static int _closed_slots[_number_of_closed_slots];