The "last seen" value for a device indicates the last time that the device responded to a SimpleMDM request. If a device is online, this is usually within an hour or two.
If the "last seen" date is longer than a few hours, it generally indicates one of the following situations:
- The device is not turned on.
- The device is without internet, or is using internet that blocks Apple push notifications or access to the SimpleMDM service. Verify that the device is able to visit the SimpleMDM website.
- The device was manually unenrolled and did not notify SimpleMDM. Verify that the SimpleMDM configuration still exists on the device.
- The incorrect Apple push certificate was renewed and uploaded to SimpleMDM around the time of the "last seen" value.
We recommend checking each of these scenarios in order to troubleshoot the issue.