With PCI compliance scans, one are often told to move TLS version to 1.2, but many clients cannot connect through a proxy to ex. Exchange. Let’s say Windows 7 with Outlook 2010. What you get when you enforce TLS 1.2, is that Outlook can no longer connect (Outlook Anywhere), it because the OS does not support higher that TLS 1.0 by default. One of the errors could be: You can fix this, by installing KB3140245… Update to enable TLS 1.1 and TLS 1.2 as a default secure protocols in WinHTTP in Windows