We have seen it working in MAC Book Air iOS version 10.10.5 Safari version 9.0.1. On iPAD and iPhone it does not load and is a known issue which will be fixed in comming releases.
I have a similar problem. In the iPhone when the user logs in via facebook or google + does not release the internet access. On the pc with Safari browser it gives error in the certificate d67iunaudm.cloud.cambiumnetworks.com.
Need more information to debug the issue,
1. Are you using ePMP HS device on baorded to Cloud or NOC version of cnMaestro
2. What exactly you ment "In the iPhone when the user logs in via facebook or google + does not release the internet access"
3. Please share AP tech dump (Open AP UI and Go to Trouble Shooting Tab and Get Techdunp)