Login window closes after successful login, but client still waiting

[JonB]

Using AnyConnect Client with corporate SAML/SSO, after completing sign-in details in the popup login window (embedded browser) there is briefly a green message shown (presumably all good) and then the pop up window closes as expected, but the AnyConnect client continues to wait for a response from the popup window.

[Marvin Rhoads]

Does the same thing occur for Windows AnyConnect clients?

[JonB]

So the issue is only affecting one computer - but this computer has a Windows VM on it too and AnyConnect works fine on Windows as long as it is set not to share the internet connection from the host Mac, instead it connects directly to the WiFi.

The problem seems to be something within the MacOS system on the specific machine - but there is no obvious setting in network settings that leaps out as potentially being the problem.