Starting with Skype for Business Cloud Connector (Cloud Connector) 1.4.1, we introduced an automated update process: Cloud Connector automatically update based on the update schedule that administrat...
Updated Feb 23, 2017
Version 7.0Blog Post
Thank you for this answer, I confirm the complete subnet on each CCE (192.168.213.*, and 192.168.214.*) has been set.
I saw in the meantime the Technet has been updated to define proxy at computer level and not user level, through a registry or GPO. will try that and post result.