Error bring network interface up: platform-linux: do-add-ip4-route[x: xx.xxx.xxx.0/24 100]: failure 101 (Network is unreachable)

Issue

When trying to bring up one of the network interfaces the following error is encountered.

Aug 26 03:41:40 hostname avahi-daemon[982]: Registering new address record for 10.20.30.2 on em2.IPv4.
Aug 26 03:41:40 hostname NetworkManager[1169]:  [1535269300.6933] platform-linux: do-add-ip4-route[3: 10.20.30.0/24 100]: failure 101 (Network is unreachable)
Aug 26 03:41:40 hostname NetworkManager[1169]:   [1535269300.6935] device (em2): state change: ip-config -> failed (reason 'ip-config-unavailable') [70 120 5]
Aug 26 03:41:40 hostname NetworkManager[1169]:   [1535269300.6937] device (eth1): Activation: failed for connection 'em2'
Aug 26 03:41:40 hostname NetworkManager[1169]:   [1535269300.6952] device (eth1): state change: failed -> disconnected (reason 'none') [120 30 0]
Aug 26 03:41:40 hostname avahi-daemon[982]: Withdrawing address record for 10.20.30.2 on eth1.