With the last update stopped working.

Explaining better: My PPPoE connection is not recognized. How can I go back to the previous version of NetworkManager?

Can you ping 8.8.8.8?
What is the output of:

lsb_release -a; uname -a

If you boot an older kernel is it better?

I restored the partition image to a previous date the updates.
I'll update again and check these items.

The connection I use is of type DSL/PPPoE

Results before system upgrade:

$ ping 8.8.8.8
PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data.
64 bytes from 8.8.8.8: icmp_seq=1 ttl=58 time=3.55 ms
64 bytes from 8.8.8.8: icmp_seq=2 ttl=58 time=3.33 ms
64 bytes from 8.8.8.8: icmp_seq=3 ttl=58 time=3.21 ms
64 bytes from 8.8.8.8: icmp_seq=4 ttl=58 time=3.84 ms
64 bytes from 8.8.8.8: icmp_seq=6 ttl=58 time=4.38 ms
64 bytes from 8.8.8.8: icmp_seq=7 ttl=58 time=3.63 ms
64 bytes from 8.8.8.8: icmp_seq=8 ttl=58 time=4.21 ms
64 bytes from 8.8.8.8: icmp_seq=10 ttl=58 time=2.96 ms
64 bytes from 8.8.8.8: icmp_seq=11 ttl=58 time=3.27 ms
64 bytes from 8.8.8.8: icmp_seq=12 ttl=58 time=3.28 ms
64 bytes from 8.8.8.8: icmp_seq=13 ttl=58 time=5.14 ms
64 bytes from 8.8.8.8: icmp_seq=14 ttl=58 time=3.54 ms
64 bytes from 8.8.8.8: icmp_seq=15 ttl=58 time=4.80 ms
64 bytes from 8.8.8.8: icmp_seq=16 ttl=58 time=3.40 ms
64 bytes from 8.8.8.8: icmp_seq=17 ttl=58 time=3.76 ms
64 bytes from 8.8.8.8: icmp_seq=18 ttl=58 time=3.84 ms
64 bytes from 8.8.8.8: icmp_seq=19 ttl=58 time=3.89 ms
64 bytes from 8.8.8.8: icmp_seq=20 ttl=58 time=3.73 ms
64 bytes from 8.8.8.8: icmp_seq=21 ttl=58 time=2.99 ms
64 bytes from 8.8.8.8: icmp_seq=22 ttl=58 time=3.68 ms
64 bytes from 8.8.8.8: icmp_seq=23 ttl=58 time=3.40 ms
64 bytes from 8.8.8.8: icmp_seq=24 ttl=58 time=3.80 ms
^C--- 8.8.8.8 ping statistics ---
24 packets transmitted, 22 received, 8% packet loss, time 23077ms
rtt min/avg/max/mdev = 2.967/3.715/5.145/0.528 ms

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu Bionic Beaver (development branch)
Release: 18.04
Codename: bionic

$ uname -a
Linux Deskpro-01 4.13.0-25-generic #29-Ubuntu SMP Mon Jan 8 21:14:41 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

Results after system upgrade:
(When restarting, the message appears for a few moments: "Connection Failed")

$ ping 8.8.8.8
connect: Network is unreachable

uname -a
Linux Deskpro-01 4.13.0-25-generic #29-Ubuntu SMP Mon Jan 8 21:14:41 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

Even using the previous kernel the problem remains.

Before the update appears the DSL/PPPoE connection (GFM DSL) and is active:
https://i.imgur.com/9YVdQlm.png

After the update it is no longer recognized:
https://i.imgur.com/6ILbcnb.png

Hello!

I was able to connect through the terminal using <$ sudo pppoeconf> and following the instructions. As for the NetworkManager, it follows dead. The DSL/PPPoE connections created with <$ sudo nm-connection-editor> are not being recognized.

It occurred on 15/03 a new network-manager update and everything indicates it's back to normal. We can consider the issue resolved.