We are experiencing inconsistent login prompt of captive portal for web authentication for WLAN, this is with Apple iPhones only. Android, Windows, and macOS devices do not experience this issue. This has been seen on Apple iPhones of various models and near-up-to-date or up-to-date iOS versions.
Environment is: all APs are associated to Foreign Controller with two virtual Mobility Anchor peers - one of those anchors handles the network traffic for this WLAN in question with the SSID requiring web authentication. We are currently using the default Cisco login page in the configuration, not a custom web auth bundle.
We see joining iPhone devices to this SSID does not always prompt the user with the login portal to authenticate to the wireless network - sometimes it will launch the prompt for login creds for authentication, but usually it does not. We have tested using multiple models of iPhone devices, testing behavior on Android as comparison (behaves expected so isolated to iPhones). We tested ensuring or disabling the auto-join/auto-login options in Settings app, and/or tried forgetting the SSID then try joining again, tried "Resetting All Network Settings", as well as after iPhone resets (Erase All) or iPhone reboots for testing completion sake.
The complete lack of presentation of the captive portal login prompt is more typical rather than the successful prompting for authentication to the user. The logs on the Anchor WLC just show No Client Response with failure to join network by client as a result.
The network does not allow authentication bypass so without this prompt, the network does not function for the end user.
Any one have any ideas? I cannot seem to find much on this issue on the new Catalyst 9800 WLC environment. Thanks!
