Live Migration (move to another Hyper-V host) VM of Authentication Manager loses all network configuration and after reboot, nothing worked and had to reconfigure IP address, mask, gateway and DNS.
Found the OS config /etc/sysconfig/network/ had new ethernet interfaces. They had to reboot then got a menu to add an IP address and hostname, just like the initial setup. A move from one hyper-V host server to another is called Live Migration, Similar to Vmotion in VMWare
After reconfiguration, network settings showed Ethernets were called eth22, eth23. Image description
The Hyper-V Virtual Machine has a Dynamic MAC address on the Ethernet Network Interface Card, NIC, which changes after reboot or Live Migration, so the Linux VM loses its IP Network settings. This is because the Linux distro binds the IP configuration to the MAC address.
From Hyper-V virtual machine settings. Assign a Static MAC address on the Ethernet Network Interface Card, NIC. In order to change this you need to power down the Virtual Machine. Unlike most controls for networking, this must be set while the VM is powered off.