For example, on my galaxy tab 4, the captive portal page does not appear after authentication to wifi. so i don't have internet access.
Can you help me ?
May I know that the strict policy of captive portal was set in your site?
Because some Android devices are not pop-up captive landing page when you set the strict policy of captive portal to "Allow HTTPS traffic without sign-on", we suggest setting the captive portal’s strict policy to 'Block all access until sign-on' allowing the captive portal page to pop-up when clients connect to the SSID.
Here's a FAQ about the captive portal CNA for your reference.
Thank you @Nebula_Freda