This is a follow-up to my previous post when I had post-upgrade issues with iOS BYOD.
Cisco ISE: 2.1
Turned out there is a bug in iOS version 10.3 beta4 and as a result 10.3.1 when profile installation fails with error message OTAMobileConfig session is invalid. This affects only new devices going through the On-Boarding process. If BYOD profile was present prior to iOS upgrade then device reconnects just fine.
If you have Cisco ISE BYOD enforcement in place notify users with iOS devices and wait for updates from Cisco.
P.S. Workaround was posted by Cisco. On Apple iDevices, go to “Settings > General > About > Certificate Trust Settings“. If the ISE root certificate shown as untrusted, manually trust the ISE root certificate and then the BYOD flow should work.