Comment 36 for bug 1586528

As niedzielski wrote on 2017-07-19:

It's clearly a IPv6 issue. Temp solution is to disable IPv6 until they can fix NetworkManager. Most of us don't need it anyway.

Add the following /etc/sysctl.conf:

  net.ipv6.conf.all.disable_ipv6 = 1
  net.ipv6.conf.default.disable_ipv6 = 1
  net.ipv6.conf.lo.disable_ipv6 = 1

Sam