Your organization has 500 new devices in Apple Business Manager.

InApple Business Manager, devices must be assigned to an MDM server before Automated Device Enrollment (ADE) will trigger. Apple Learning notes that if devices, such as iPhones, are added but left without adefault MDM server assignment, they will not prompt for enrollment during setup. Macs may already have been assigned properly, which explains why they enroll as expected. Wrong locations or approval queues do not exist in ABM for ADE devices, and while a device reset is required to trigger ADE, the absence of a server assignment is the root issue here. Once the devices are assigned to the correct MDM server, users will see the ADE flow during setup. This is a common misstep in large deployments.