Client connected to the SSID, gets the DHCP config but no captive portal redirection for the username/password, hence no internet access. Manually typing the url of the captive portal/ZD works fine.
- the controller was previous running on 9.6 version and now running on 9.8 version. There is a known software bug on the ZD which are upgraded from 9.6 to 9.8. - TAC engineer went into the ZD shell mode and applied the fix on the necessary files (added missing firewall rules) - rebooted the controller - redirection started working