Palo Alto - Captive Web Portal - iOS Auto Login not working

[Arcolite]

We're just in the process of setting up Captive Web Portal on our Palo Alto firewall.

 

Everything is setup and working fine. On Windows devices, after a user has connected to the SSID they are redirected to the CWP as soon as they open a browser window.

However on iOS devices, as soon as they connect to the SSID they get the iOS Auto-Login windows pop-up which is supposed to load the CWP. Instead however, it looks like it's trying to go to captive.apple.com, then presents an error message.

 

 

I can make the error go away by allowing these requests through without CWP auth, however doing that stops the Auto-Login happening completely (because iOS can't see the CWP anymore!).

iOS users have to manually open Safari (or Chrome) and browse to a website in order to Authenticate.

 

 

Has anyone been able to get the Auto-Login working with Palo Alto CWP?