I recently had my device replaced at the apple store. Installing builds from TestFlight failed, so I logged in to http://testflightapp.com in Mobile Safari, went to https:/www.testflightapp.com/m/connectdevice, and tapped "Reconnect Device". The profile downloads and attempts to install, but consistently fails with the error "The SCEP server configuration is not supported."
This SO discussion of a similar error suggests it's a firewall issue, but I've tried it on my home wifi, on 3G, and LTE, always with the same results.
I've also tried rebooting my device a couple of times, to no avail.