diff --git a/lib/resty/etcd/v3.lua b/lib/resty/etcd/v3.lua
index 437050eb..9d3c2fd8 100644
--- a/lib/resty/etcd/v3.lua
+++ b/lib/resty/etcd/v3.lua
@@ -142,7 +142,7 @@ local function _request_uri(self, method, uri, opts, timeout, ignore_auth)
         end
     else
         local max_retry = #self.endpoints * health_check.conf.max_fails + 1
-        for _ = 1, max_retry do
+        for i = 1, max_retry do
             res, err = http_request_uri(self, http_cli, method, uri, body, headers, keepalive)
             if err then
                 if err == "has no healthy etcd endpoint available" then
@@ -152,9 +152,16 @@ local function _request_uri(self, method, uri, opts, timeout, ignore_auth)
             else
                 break
             end
+            if i == max_retry then
+                return nil, err
+            end
         end
     end
 
+    if not res then
+        return nil, "request etcd get nil response"
+    end
+
     if not typeof.string(res.body) then
         return res
     end