diff --git a/gfw/api/client.go b/gfw/api/client.go
index bb8d6ee..2436502 100644
--- a/gfw/api/client.go
+++ b/gfw/api/client.go
@@ -62,6 +62,8 @@ func (c *GFWClient) doRequest(req *http.Request) ([]byte, error) {
 	if res.StatusCode >= 500 {
 		if err != nil {
 			return nil, err
+		} else {
+			return nil, fmt.Errorf("Error %d: %s", res.StatusCode, string(body))
 		}
 	}
 	if res.StatusCode >= 300 && res.StatusCode < 500 {