Try Settings > Safari > Clear website data. Then try to connect again. captive.apple.com appears to be a legitimate website that returns the word "Success", possibly to confirm that an internet connection exists.

How do you get past the captive Apple?

There's only one way to avoid the captive.apple.com portal page that appears when you connect to a public Wi-Fi hotspot. Wi-Fi portals use an ugly hack to intercept a connection when the venue wants you to either pay, log in with an account, or accept terms before using a free network.

Why captive Apple Com is not working?

Please try to reboot your MacBook into Safe Mode (holding the shift key on boot). If the Captive Portal appears it is likely a 3rd party application that is interfering with the Network Stack. When you reload you PC back into Normal Mode you should be connected, however that doesn't necessarily mean it is fixed.