Comment # 2 on bug 900376 from Bernhard Wiedemann

So is that a fresh install of 13.1
or did you upgrade the old 12.1 directly to 13.1?
The latter may or may not work, but is certainly not supported.

DNS working, but failure in fetching data, points towards routing being lost,
which you could verify using the command
ip r


also important to debug this is the last part of /var/log/zypp/history
and /var/log/zypper.log
which would show the last package to be installed before the breakage.

One possible workaround would probably be to use yast2 lan
to switch from NetworkManager to ifup handling the network