diff --git a/conn_opt.go b/conn_opt.go
index a2f184f..e2f8ab5 100644
--- a/conn_opt.go
+++ b/conn_opt.go
@@ -60,7 +60,7 @@ func LogMessages(log *log.Logger) ConnOpt {
 					log.Printf("--> result #%s: %s: %s", resp.ID, method, result)
 				case resp.Error != nil:
 					err, _ := json.Marshal(resp.Error)
-					log.Printf("--> error #%d: %s: %s", resp.ID, method, err)
+					log.Printf("--> error #%s: %s: %s", resp.ID, method, err)
 				}
 			}
 		})(c)
diff --git a/handler_with_error.go b/handler_with_error.go
index 006018d..11cd945 100644
--- a/handler_with_error.go
+++ b/handler_with_error.go
@@ -37,7 +37,7 @@ func (h HandlerWithError) Handle(ctx context.Context, conn *Conn, req *Request)
 
 	if !req.Notif {
 		if err := conn.SendResponse(ctx, resp); err != nil {
-			log.Printf("jsonrpc2 handler: sending response %d: %s", resp.ID, err)
+			log.Printf("jsonrpc2 handler: sending response %s: %s", resp.ID, err)
 		}
 	}
 }