If this error appears when adding a player from the Provision screen, the player already has an existing provisioning record under another BSN.cloud network.
A player can only have one provisioning record in BSN.cloud so to provision the player, the player’s existing provision record must be deleted and the player removed from its current network.
To do this, follow the steps outlined here. Only the owner of the network to which the player belongs can perform these functions so you may have to contact that person to request that they do this.