Are you still using Quicken on Windows XP?
That's no longer
supported. Sorry. Please read this:
Are you still using Windows Vista?
As of April 11,
2017, Microsoft has discontinued support for Windows Vista.
Quicken 2016+ is no
longer supported with Vista. It may install and run, but only if you have
updated Vista and IE9 to support TLS 1.2 security protocol. See https://msfn.org/board/topic/176902-enabling-tls-1112-support-in-vistas-internet-explorer-9
Do not forget to enable TLS 1.2 in Internet Options!
(Also see: https://getsatisfaction.com/quickencommunity/topics/qp2017-r17-2-build-26-1-17-2-one-step-update-error-ol-297-a-sunable-to-establish-internet-connection
Still using Windows 7 SP1?
(This may also apply to Windows 8 or 10)
Ensure that TLS 1.2 is enabled in Control Panel / Internet Options.
In Windows Control Panel select Internet Options (or in Internet Explorer,
click on Tools / Internet options.)
Click the Advanced tab.
Scroll down the list to "Use TLS x.x" and click to put a checkmark on
all available TLS choices, 1.0, 1.1 and 1.2.
Click Apply, then OK. Close IE. Close and restart Quicken.