Change the DNS Server in your Browser to use OpenDNS or GoogleDNS.
Open Settings in Edge, type DNS in the Search Bar, it will show up under Security, "Use Secure DNS to specify..." Choose "Choose a service provider" and choose one of the above.
In Chrome, same thing ... open Settings, Search on DNS, Use Secure DNS, and choose one of the above.
Restart your browser and try again.
https://www.reddit.com/r/AirForce/comments/tmljtq/accessing_portal_from_home_computer/