It seems like NetworkManager kills itself if there is something wrong in the system. I face similar bug with connected serial port https://bugzilla.kernel.org/show_bug.cgi?id=121521
** Bug watch added: Linux Kernel Bug Tracker #121521 http://bugzilla.kernel.org/show_bug.cgi?id=121521 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1380480 Title: network disabled after suspend - resume To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux-lts-xenial/+bug/1380480/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs