Why can't the network start on pure ubuntu?

Question

System administration

I create a droplet on digitalocean, install ubuntu 16.04 x64, all the rules start, and so on. It is worth restarting the droplet and the network does not start either automatically or manually. What could be the problem? I don’t touch configs and other things, I just set a new password at the first login (OS requirement).

spoiler

network configs

# This file describes the network interfaces available on your system 
# and how to activate them. For more information, see interfaces(5). 

# The loopback network interface 
auto lo 
iface lo inet loopback 

# Source interfaces 
# Please check /etc/network/interfaces.d before changing this file 
# as interfaces may have been defined in /etc/network/interfaces.d 
# See LP: #1262951 
source /etc/network/interfaces.d/*.cfg

The one that is attracted through * .tsfg

# This file is generated from information provided by 
# the datasource. Changes to it will not persist across an instance. 
# To disable cloud-init's network configuration capabilities, write a file 
# /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg with the following: 
# network: {config: disabled} 
auto lo 
iface lo inet loopback 

auto eth0 
iface eth0 inet static 
address 207.154.214.64 
dns-nameservers 8.8.8.8 8.8.4.4 
gateway 207.154.208.1 
netmask 255.255.240.0 
post-up ifup eth0:1 


auto eth0:1 
iface eth0:1 inet static 
address 10.19.0.5 
netmask 255.255.0.0

Answer 1

In general, the problem was solved by removing the droplet and creating a new one with a new ip

Answer 2

If the network is not via DHCP, with manual settings, then it is very likely that the MAC address of the network card changes after a reboot, it is perceived as a new device and needs to be configured again.