anyconnect vpn certificate validation failure

When clicking on 'Connect' on the An圜onnect client, user is not prompted for a username/pw but instead receive the certificate validation error User was able to log into their Windows account using their old credentials (they magically remembered them today) but not the pw we gave them yesterday We were able to change their AD password and get the system updated with the new credentials yesterday afternoon, but shortly thereafter the user's computer BSOD for thermal issues (we'll be replacing the machine soon, but they are about 6 hours away from our office so that is not feasible immediately). This remote user forgot their password and needed to have it reset. My problem is a little more specific, so I was hoping someone may have seen something like this in the past.

My google fu returned some results for the issue, but they all seemed to be related to resolving then issue on the ASA itself. I received a call from a remote user who gets the Cert Validation error when trying to connect their Cisco anyconnect client. My official title is helpdesk technician, but we are currently operating without any sysadmins so my knowledge of our network configuration is limited at best, but I'll do my best to answer any questions that might help. Hopefully this is the right place to post this.

Anyconnect vpn certificate validation failure