I learned about neverssl.com from François Vergès a while ago, and now another option for “tricking” your device to make a captive portal trigger.
Here are a couple other options:
To trigger an Apple captive portal login page, try manually browsing to the non-HTTPS URL https://lnkd.in/gtvuyQ_g in Safari.
If that fails, you can also try connecting to the network, disabling your cellular data, and then opening http://1.1.1.1.
Other methods include restarting your device, forgetting and reconnecting to the network, or browsing a non-HTTPS site like http://example.com.