Mac Safari Can't Establish Secure Connection to Graphisoft websites

[Steve Campbell]

We can't connect to any of the Graphisoft websites using Safari or Firefox on macOS Sequoia 15.5. This includes the Graphisoft ID server, BimX Model Transfer, our BimCloud SaaS Server, and this site. We also can't publish BimX models directly to BimX Model Transfer from inside ArchiCAD 28.

We can connect using Chrome so I don't think it's a firewall or network setting on our end. We've emptied caches and cleared the browser history with no luck.