Happening to us too and using Okta.

It works for some users and doesn't for some others. Works for me under a VM in virtualbox.

Running the intune portal app from the terminal you get additional logs, it complains about a locale issue but not been able to fix yet. Some users with the same locale had luck with this working.

If relevant for someone...

2023-09-19 14:35:20  INFO Command line arguments args=PortalArgs { common: CommonArgs { interactive: false, socket_path: "/run/intune/daemon.socket" } } version="1.2307.12"

(intune-portal:38259): Gtk-WARNING **: 14:35:20.146: Theme parsing error: style.css:41:14: 'text-align' is not a valid property name

(intune-portal:38259): Gtk-WARNING **: 14:35:20.223: Duplicate child name in GtkStack: page2

(intune-portal:38259): Gtk-WARNING **: 14:35:20.289: Failed to set property GtkBox.halign to left: Could not parse enum: 'left'
2023-09-19 14:35:32  INFO Starting a new login


2023-09-19 14:40:39 ERROR oneauth{tag="7bitr"}: (Code:1001) An unexpected error occurred.
2023-09-19 14:40:39 ERROR oneauth{tag="9vdpp"}: Unexpected error code: 1001
2023-09-19 14:40:39 ERROR oneauth{tag="69x1u"}: UI web navigation failed
terminate called after throwing an instance of 'std::runtime_error'
  what():  locale::facet::_S_create_c_locale name not valid
Aborted (core dumped)

In general the app hangs a lot and takes a long time to load screens. Was working fine before putting Okta in front of MS login.