Mac doesn't load the login page of public Wi-Fi

I have a user who is experiencing the same problem with multiple different public WiFi networks after being upgraded to Mojave.

I found this article - here.

According to that, Apple made a change in Mojave so that public WiFi 'Captive Portals' need a fully qualified domain name and a matching official i.e. trusted SSL certificate.

The problem is many such public WiFi systems use 'self signed' certificates and these will not be trusted by a visiting user i.e. you. Hence Mojave rejects them.

I suspect the intent by Apple is to prevent you connecting to a random fake public WiFi that a cyber criminal has setup in order to attract people and then monitor their internet traffic.

Note: It is a good idea to always use a VPN when using a free public WiFi.

It maybe that this security change in Mojave is not targeted at public WiFi Captive Portals specifically but a side effect of the fact that the Captive Portal login is displayed in Safari and that Safari is enforcing stricter security over accessing all websites including the Captive Portal.

Since this is likely to be an increasingly common problem as both the adoption of Mojave increases and as other operating systems including those on mobile devices adopt similar measures I would expect that many of the bigger organisations will hopefully soon switch to using proper trusted certificates. Whether smaller organisations will get round to this is unknown.