Cisco VPN Anyconnect stopped working

About three days ago (after years of using) my daughter started experiencing issues with connecting to her George Mason University VPN via vpn.gmu.edu, vnp.gmu.edu/student via Cisco AnyConnect client. Cisco client cannot reach the domain, suggesting No Internet. Internet keeps working just fine.

She connects fine via Hot Spot (AT&T cellular data), from campus Wi-Fi, from the local public library. Several days GMU IT could not resolve the issue, narrowing it down to our Internet provider. Everyone else connects as usual (Verizon, AT&T customers).

How can I reach out to Comcast Infinity so they could check their recent firewall changes and white-list George Mason University VPN domains?