Cisco Anyconnect Cannot Connect To Secure Gateway

This article refers to the Cisco AnyConnect VPN. If you're looking for information on the Prisma Access VPN Beta that uses the GobalConnect app, see: Prisma Access VPN Landing Page.
If you're not sure which service you're using, see: How do I know if I'm using the Cisco AnyConnect VPN or the Prisma Access VPN?

What should be done when an attempt to connect to VPN using Cisco AnyConnect generates this message: AnyConnect was not able to establish a connection to the specified secure gateway. Please try connecting again.

A resource for employees to connect remotely using Cisco AnyConnect VPN (also referred to as RESCUE) or the Citrix Access Gateway (CAG). If you are experiencing problems connecting, please contact the Enterprise Service Desk at 855-673-4357 (TTY: 1-844-224-6186). Citrix Access Gateway (CAG). Captive Portal Hotspot DetectionAnyConnect displays the “Unable to contact VPN server” message on the GUI if it cannot connect, regardless of the cause. VPN server specifies the secure gateway. If always-on is enabled, and a captive portal is not present, the client continues to attempt to connect to the VPN and updates the status message.

AnyConnect VPN Client FAQ

Cisco Anyconnect Cannot Connect To Secure Gateway

Cisco AnyConnect VPN Client

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In the Windows Control Panel navigate to Internet options (Network and Internet Connections, and then Internet Options)

How to fix “AnyConnect was not able to establish a connection ...

Once there, the user will need to select the Connections tab, and then LAN Settings. Make sure the option 'Use automatic configure script' is unchecked, reboot, and then retry Cisco AnyConnect.