Why does not connect to the Linux network after a reboot?

Question

linux

Good day! Straight to the point
Ubuntu 16.04.3 LTS

There are two networks that I use for the machine, when switching from one to the other (I do this physically due to the specifics of the equipment), both networks stopped working. That is, if there is a connection, in ifconfig I see only 127.0.0.1, when I decided to look
dhclient -v

it gave out:

/var/lib/dhcp/dhclient.leases line 25: lease specified for unknown pseudo.
   expirelease {
/var/lib/dhcp/dhclient.leases line 26: expecting semiclolon.
   interface
Can't allocate interface enp1slease {
   interface

What could be the problem and how to solve it, not very experienced in Linux

Answer 1

Solved the problem by deleting /var/lib/dhcp/dhclient.leases