diff --git a/headers/client.h b/headers/client.h
index e70489385158fd3b690407400a7063e59587601f..f06619b20d8807d7c37997ad777cbe055dca3b21 100644
--- a/headers/client.h
+++ b/headers/client.h
@@ -79,7 +79,7 @@ frame *client::receive_ack(frame *f)
   // esperando, continuamos tentando receber
   do {
     ack_res = socket->receive_frame();
-    if (ack_res->get_tipo() == ERRO) 
+    if (ack_res && ack_res->get_tipo() == ERRO) 
     { 
       cout << "Espaco insulficiente no destino\n";
       return NULL;