Tunnel from primary and secondary hubs to one of the Robot Hubs is not being established; Around 90 Servers are now not monitored.
Communications from the Primary and Secondary servers to the Robot Hub TCP port 48003 has been verified and it´s possible:
Primary and Secondary are installed on Linux servers and Robot hub in a windows server.
Errors are shown in the primary hub.log such as:
Nov 25 19:10:17:051  hub: CTRL <hub1_name> could not resolve address <hub2_name>:48003
change in the customers domain meant the hub could not resolve host names to IP addresses.
Release : 9.0.1
Component : UNIFIED INFRASTRUCTURE MGMT
adding entries to the local hosts file allowed it to resolve correctly and connection was re-established