We seem to have random onesie or twosie iPads that absolutely refuse to reach the activation server. I'm working on an iPad now and even after removing it from an ASM assignment (and Jamf prestage) and then putting it back in, it gets the refusal messages of:
(1) "Remote Management - The config for your iPad could not be downloaded"; and
(2) "Could not reach activation server - try again".
Any tips or tricks to suggest before I go for the longshot route of deleting it from ASM and doing the Apple Configurator 2 trick of adding it back to ASM and see if that resolves the issue?
I recommend to make sure that the device is showing up in Prestage Enrollments and it is checkmarked and assigned. If it is, then DFU wipe the device and choose a different network, say, hotspot. It sounds like the configuration is timing out.
Also if the device is in ASM, I would not touch if it's in there already and in the correct MDM server if you have multiple.