diff --git a/docs/registry.go b/docs/registry.go
index 5b8480d18..1e0e1815d 100644
--- a/docs/registry.go
+++ b/docs/registry.go
@@ -391,7 +391,7 @@ func (r *Registry) PushImageJSONRegistry(imgData *ImgData, jsonRaw []byte, regis
 	if res.StatusCode != 200 {
 		errBody, err := ioutil.ReadAll(res.Body)
 		if err != nil {
-			return utils.NewHTTPRequestError(fmt.Sprint("HTTP code %d while uploading metadata and error when trying to parse response body: %s", res.StatusCode, err), res)
+			return utils.NewHTTPRequestError(fmt.Sprintf("HTTP code %d while uploading metadata and error when trying to parse response body: %s", res.StatusCode, err), res)
 		}
 		var jsonBody map[string]string
 		if err := json.Unmarshal(errBody, &jsonBody); err != nil {