Please upgrade the "curl.exe" that are packaged with Designer from 7.15 to 7.55 or greater to allow for -k flags. Also please allow the -k functionality for the Atleryx Download tool.
-k, --insecure
(TLS) By default, every SSL connection curl makes is verified to be secure. This option allows curl to proceed and operate even for server connections otherwise considered insecure.
The server connection is verified by making sure the server's certificate contains the right name and verifies successfully using the cert store.
Regards,
John Colgan