Even though this Jamf Nation thread is five years old, as of this writing, it’s still got the solution to the
Device Signature Error - A valid device signature is required to perform the action error message.
In my experience, the actual working solution is to run
sudo jamf enroll -prompt and then enter credentials when prompted. Repeatedly running
sudo jamf recon (even after a reboot) or
sudo jamf policy doesn’t fix the issue, nor does verifying that the system clock time is correct.
Now why this comes up in the first place on a freshly factory-reset computer that DEP-enrolled in Jamf—who knows but Jamf?