DEP Enrollment (ios) only works sporadically since 29/10/19

Hi trebelow!

A couple of questions for you:

Is this a new device?
Is one device affected, or multiple?

Profile Installation Failed. A Network Error Has Occurred:
This can sometimes occur if there is an issue with iOS for that device.

Resolution:
This can be resolved when the device is Factory Reset, and can be done by putting the device in DFU mode (Device Firmware Update Mode) and restoring iOS. Once this is completed, the device should be able to enroll successfully. More information on how to restore iOS can be found on Apple's support site here: If you can't update or restore your iPhone, iPad, or iPod touch.

Installing configuration from CompanyName - Profile Installation Failed. The SCEP server returned an invalid response:

This is often caused by an issue with the device itself. If you experience this error with only one device, or a limited subset of DEP devices, this is likely the case.

Resolution:

There are a few things we can validate and try before resorting to factory resetting the device such as:

• Validate that the iOS Platform is set to Allow within the Intune Portal: https://docs.microsoft.com/intune/enrollment/enrollment-restrictions-set
• Validate if a non-DEP iOS enrollment works on the same Wireless network
• Try connecting from a different Wireless network or using a Cellular network (Hotspot)

Also, feel free to private message us your support case for us to follow-up on.

Hope this helps!
Intune Support Team
^MS