diff --git a/doh-server/ietf.go b/doh-server/ietf.go
index c3535b14b5f81a73fc13562d4bc755360bf7e31c..a4503a9d68e79823b2ed77a0dd9cf271a372a006 100644
--- a/doh-server/ietf.go
+++ b/doh-server/ietf.go
@@ -62,7 +62,7 @@ func (s *Server) parseRequestIETF(ctx context.Context, w http.ResponseWriter, r
 	if len(requestBinary) == 0 {
 		return &DNSRequest{
 			errcode: 400,
-			errtext: fmt.Sprintf("Invalid argument value: \"dns\""),
+			errtext: "Invalid argument value: \"dns\"",
 		}
 	}