Receiving error: "The SCEP server configuration is not supported" when provisioning an iOS device.
Uninstall the Network Device Enrollment Service (NDES) role service.
Reinstall the NDES role service and specify the updated username/password for the user account when prompted to enter the account credentials.
It is recommended to use a user account that has the "Password never expires" option selected.
If this was caused by expired certificates you may also wish to just renew the RA certificates, should you not wish to reinstall NDES.