blower

Unfortunately that's no good if you are accessing a 3rd party server beyond your control.

I have run into the same problem with the RESTClient (and any HTTPS based controls for that matter), and i suspect the issue you are having with windows 7, is due to the limited cipher suites available on 7 and 8.1 Some servers have switched to using strong cipher's for their TLS...and merely enabling TLS 1.2 will not work on operating systems older than Windows 10. I've seen some servers only support TLS ciphers such as TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 These are not supported on Windows 7 (and i believe neither on 8.1) - there is no way to add them either. Microsoft in their (lack) of wisdom never added them on their final cipher update, despite them being in use at the time, and now these OS's no longer receive any mainstream support and are considered EOL, they won't ever add them. If you try to connect to a server which uses the above ciphers for TLS, on windows 7, you will get the 12175 security error. You can see what ciphers are supported on windows 7 here: https://docs.microsoft.com/en-us/windows/win32/secauthn/tls-cipher-suites-in-windows-7 You can test your servers SSL certificate here to find out what TLS ciphers it supports: https://www.ssllabs.com/ssltest If the server supports ciphers on the list, and yet you are still getting the error then the previous posts for enabling TLS1.2 on windows 7 may work, you may also have to set the appropriate SecureProtocols property on the RESTClient.