Profile Installation Failed. The SCEP server returned an invalid response

Hello,

I'm activating iOS DEP devices and I am receiving an error "Profile Installation Failed. The SCEP server returned an invalid response", the issue occurs both on Wi-Fi and mobile network.

These are straight out of the box devices, I did some digging and I found this article https://support.citrix.com/article/CTX206952 , I followed step 2 which is a full OS wipe and I was able to successfully activate the device.

As we have 400+ devices already distributed to users across EU we do not want to wipe them one by one.

Is anyone able to explain why this is happening and if there is another solution?