I am getting the following emails after subscription creation:
Usage of capacity 'Websites' on host '2' has been reached the limit (0), current consumption is Usage of capacity 'Mailboxes' on host '3' has been reached the limit (0), current consumption is 181.
But I have unlimited Plesk license.
In Plesk Automation 11.5 Service Nodes Capacity Control feature was added. Since PA 11.5 you can define the maximum number of websites and mailboxes you would like to host on a particular service node.
Notification is set, because current
Mailboxes count is higher than limit, you should increase "Capacity" and "Warning level" values if you do not want to receive such notifications. Go to Infrastructure > Service Nodes > node ID from notification > General > Capacities