In admin panel "Sharing - Screen Sharing". Dialog box, (bottom "Network" part of it) says there is "No networks selected for sharing". (Nothing to select) Server don't detect actual working wired connections.

[PG]

Problem: In admin panel "Sharing - Screen Sharing" dialog, not able to activate Screen Sharing.

The Screen Sharing dialog box, (bottom "Network" part of it) says there is "No networks selected for sharing". It should at least show "Wired Connection 1", as in fact the wired connection is working perfectly (the box has internet connection in and out, and I am able to connect to it using ssh).

As the sharing dialog does not show any available networks to pick from, it is not possible to activate the sharing.

Another problem indicator is that the desktop systray network icon does not show up, even if the box is connected to fully working wired ethernet connection, and internet is working in and out of the machine.

Also, in admin panel "Network" configuration dialog, there is no visible config area for "Wired Connections". It appear as the computer has no network cards at all, only the VPN and Proxy settings are visible.

*****

Possible related problem with drivers: I tried 'ubuntu-drivers devices' in order to find correct drivers for my graphic card. The output from the command was simply nothing at all, it just reverted to the empty clean command prompt.
root@mybox:~# ubuntu-drivers devices
root@mybox:~#

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: network-manager 1.10.6-2ubuntu1
ProcVersionSignature: Ubuntu 4.15.0-20.21-generic 4.15.17
Uname: Linux 4.15.0-20-generic x86_64
ApportVersion: 2.20.9-0ubuntu7
Architecture: amd64
Date: Fri May 4 18:18:02 2018
IfupdownConfig:
 # ifupdown has been replaced by netplan(5) on this system. See
 # /etc/netplan for current configuration.
 # To re-enable ifupdown on this system, you can run:
 # sudo apt install ifupdown
InstallationDate: Installed on 2018-04-29 (4 days ago)
InstallationMedia: Ubuntu-Server 18.04 LTS "Bionic Beaver" - Release amd64 (20180426)
IpRoute:
 default via 192.168.0.1 dev enp4s0 proto dhcp src 192.168.0.199 metric 100
 192.168.0.0/24 dev enp4s0 proto kernel scope link src 192.168.0.199
 192.168.0.1 dev enp4s0 proto dhcp scope link src 192.168.0.199 metric 100
IwConfig:
 enp5s0 no wireless extensions.

 lo no wireless extensions.

 enp4s0 no wireless extensions.
NetworkManager.state:
 [main]
 NetworkingEnabled=true
 WirelessEnabled=true
 WWANEnabled=true
RfKill:

SourcePackage: network-manager
UpgradeStatus: No upgrade log present (probably fresh install)
nmcli-con: NAME UUID TYPE TIMESTAMP TIMESTAMP-REAL AUTOCONNECT AUTOCONNECT-PRIORITY READONLY DBUS-PATH ACTIVE DEVICE STATE ACTIVE-PATH SLAVE
nmcli-dev:
 DEVICE TYPE STATE DBUS-PATH CONNECTION CON-UUID CON-PATH
 enp4s0 ethernet unmanaged /org/freedesktop/NetworkManager/Devices/2 -- -- --
 enp5s0 ethernet unmanaged /org/freedesktop/NetworkManager/Devices/3 -- -- --
 lo loopback unmanaged /org/freedesktop/NetworkManager/Devices/1 -- -- --
nmcli-nm:
 RUNNING VERSION STATE STARTUP CONNECTIVITY NETWORKING WIFI-HW WIFI WWAN-HW WWAN
 running 1.10.6 disconnected started unknown enabled enabled enabled enabled enabled

[PG (htpc-c)]

Problem solved

Cleaned /etc/netplan and replaced the content with this: https://paste.ubuntu.com/p/PSWHYgdQrZ/

Rebooted, and all working

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Kees Bakker (keestux)]

It may be that @PG found a workaround, that doesn't mean the problem has gone away.

If the network is managed by the system administrator, then the screen sharing dialog doesn't see the network. This is rather unfortunate. I don't want the user to be able to change the network, but I do want the user to be able to share the screen.

[Kees Bakker (keestux)]

So, I don't think it's a network manager bug. It's the thing that's presenting the screen sharing dialog.

[Sebastien Bacher (seb128)]

@PG, what netplan config did you have before?

> If the network is managed by the system administrator,

What do you mean there? How is it configured?

[Launchpad Janitor (janitor)]

[Expired for gnome-control-center (Ubuntu) because there has been no activity for 60 days.]

[Swinder Pal Singh (swinder0161)]

Need help on same problem

My company admistrator manages the network and hence the wired connection shows up as unmanaged in NM ui.
Screen Sharing doesnot allow to enable as no network available in the list to select.