Same issues, check out my testing: https://communities.cisco.com/message/293975#293975   Agreed, only way I could get this to work was to bypass CNA which my customer is not happy about...    Summary:   -2504 Running 8.3, MAB, AAA override and ISE NAC. I get the pop up, enter creds, and are redirected to the success page and it works fine on IOS, MACOS, Windows.   -Meraki MR34, MAB, ISE for Radius and "Use ISE for splash page". My IOS devices get the pop up, enter creds, and get a 400 Error. Works fine on Windows and MACOS.   So, I tried this: -Meraki MR34, MAB, ISE for Radius and "Use ISE for splash page". Added 17.0.0.0/8 into the walled garden list (nslookup on apple.com), and the CNA browser did not pop up. I opened a browser manually (fail, default was https://www.google.com), went to a http (no s) site, my Splash page came up, enter creds, and logged in just fine. ... View more

You will want to have Meraki support enable Walled Garden domains so you can use URLs in the walled garden allowed list. This disables the captive portal detection and makes you manually open a webpage, or on Android you can just click the Wireless network after it's connected and it will take you to the redirect page. This worked for us. It is still flaky sometimes. On Apple devices, you still have to type http:// to force it to not use https to begin with. Once it's in your browser cache it sees it as https from then on and that is what is causing the issue. Follow the link below to see the domains to add and open a case with support to have Walled Garden Domains enabled. It's still in beta but does not hurt being turned on even if you do not use it.    https://documentation.meraki.com/MR/Encryption_and_Authentication/Central_Web_Authentication_(CWA)_with_Cisco_ISE ... View more