Gateway error

Hi everybody !

When I want to connect my email to Gateway at the end of the installation, I have this error..

La demande de réseau a retourné une erreur inattendue.
The remote server returned an error: (502) Bad Gateway.
   at System.Net.HttpWebRequest.EndGetRequestStream(IAsyncResult asyncResult, TransportContext& context)
   at System.Net.Http.HttpClientHandler.GetRequestStreamCallback(IAsyncResult ar)

Could anybody know what it mean ?

Thanks

Best regards

David