diff --git a/cmd.go b/cmd.go
index d725d3a..3184f2f 100644
--- a/cmd.go
+++ b/cmd.go
@@ -1037,7 +1037,7 @@ func (cmd commandStor) Execute(conn *Conn, param string) {
 		msg := "OK, received " + strconv.Itoa(int(bytes)) + " bytes"
 		conn.writeMessage(226, msg)
 	} else {
-		conn.writeMessage(450, fmt.Sprintln("error during transfer:", err))
+		conn.writeMessage(550, fmt.Sprintln("error during transfer:", err))
 	}
 }