diff --git a/internal/handler/letter_outgoing_handler.go b/internal/handler/letter_outgoing_handler.go
index aa1b925..b8d190a 100644
--- a/internal/handler/letter_outgoing_handler.go
+++ b/internal/handler/letter_outgoing_handler.go
@@ -383,7 +383,7 @@ func (h *LetterOutgoingHandler) AddAttachments(c *gin.Context) {
 		return
 	}
 
-	c.JSON(http.StatusOK, &contract.SuccessResponse{Message: "attachments added"})
+	c.JSON(http.StatusOK, contract.BuildSuccessResponse(&contract.SuccessResponse{Message: "attachment added"}))
 }
 
 func (h *LetterOutgoingHandler) RemoveAttachment(c *gin.Context) {