diff --git a/metadapta.go b/metadapta.go
index 06f2701..5517c88 100644
--- a/metadapta.go
+++ b/metadapta.go
@@ -94,7 +94,7 @@ func (this *a) unlistTransactionSafe(id int64) {
 
 func (this *a) sendMessageSafe(trans int64, method uint16, data []byte) error {
 	this.sendLock.Lock()
-	defer this.sendLock.Lock()
+	defer this.sendLock.Unlock()
 	return encodeMessageA(this.underlying, trans, method, data)
 }