Comment 31 for bug 1841040

I *think* there is better and more pleasant workaround rather than rebooting every time this bug affects you.

Try putting your computer into suspension, then wake it up.
In most of the cases Ethernet interface fails to start at all. If it does, then reloading its driver may help it this point:

# modprobe -r r8169
# modprobe r8169

This worked for me on 5.0.0-25-generic.