Cisco AnyConnect 'could not connect to server' issue

[gw2dave]

We've been struggling trying to figure out what's wrong with a VPN user yesterday as all of the sudden, the user was disconnected and was not able to connect to the VPN. It keeps giving the 'could not connect to server error. Please verify internet connectivity and server address'. I've uninstalled the client, even setup up a different laptop, installed the new Anyconnect client but still getting that error. I verified that the laptop is connected to the internet. 

Any suggestions/ideas? TIA

[Marvin Rhoads]

Is the laptop resolving the FQDN for the gateway properly? Can they browse to the web portal?

[gw2dave]

It does not. I have someone check our ASA and wasn't able to see incoming connections from the laptop's IP. I am able to connect to a website just fine but not our vpn server.

[Marvin Rhoads]

So something is preventing the client's DNS resolver from working properly. "Resolve" that issue and things should start working.

You can verify that's the problem by entering your ASA's IP address in AnyConnect. You will have to click past the untrusted server warning since the certificate doesn't generally have the IP address; but otherwise they should be able to connect.

[Sheraz.Salim]

Just to add what @Marvin Rhoads said. could you double check if your DNS records for the anyconnect FQDN is still vaild (could be someone in your team change the DNS record).