When provisioning a Juniper Switch into MIST, you may note it gets connected but it does not move forward so, no stats are sent to the cloud.

The switch will show connected but, it will not update any stats: Name will remain with its MAC address, if it is a VC it will not display all members; and in general, no stats nor switch events will be seen at all.

The switches will not be able to retrieve any stats if they have JET Services disabled through the command: set system processes jsd disable.

Therefore, it is required to make sure that line is not present and, if present, to remove it: delete system processes jsd disable