Aliexpress 400 error

I can’t use my Aliexpress API key. I have entered my App Key but I cannot enter App Secret, how should I proceed? I have this error that appears in the search fields.

HTTP request status fails: 400 - Bad Request. Server replay: {"error_message":"Invalid appKey.","exception":"Invalid appKey.","error_code":"gw.AppKeyNotFound","request_id":"XXX"}