Why is my VM stuck with a status of "enrolling"?

When attempting to enroll a Virtual Machine in SimpleMDM, a common problem is that the device will get stuck and fail to complete the enrollment process. The Status column on the Devices list will usually show the device as "Enrolling".

In these situations, we have found that the issue is frequently a result of special characters ("+","/", etc.) being inserted into the device's serial number generated by the VM software. To resolve this, update the VM's serial number to match a valid macOS format - typically they should be 12 characters long using only numbers and letters.