How to troubleshoot odd ethernet connect error?

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I just upgraded my Dell XPS (M1530) laptop to Fedora 28 (Fedora Scientific), and the ethernet connection no longer comes up at boot when I'm at work. (It always did in the old Fedora 18 system.) Nor can I bring it up manually:

  $ nmcli con up enp9s0
  Error: Connection activation failed: No suitable device found for this connection.

The odd thing, though, is that it (the ethernet connection) does come up (both automatically at boot, and manually from the command line) when I bring the machine home. The failure is only at work.

I'm a fairly experienced Fedora user, but unfortunately am not knowledgable about how to troubleshoot network connection problems. Where do I start looking--given that this problem is clearly not due to hardware failure or (it appears) to the network driver (since the problem doesn't occur when I bring the machine home)?

For the record, here's the ifcfg file for the ethernet connection:

  NAME=enp9s0
  TYPE=Ethernet
  HWADDR=00:23:AE:19:90:4B
  UUID=bda4a6ba-acb1-4c3f-88de-a7d245942dd6
  ONBOOT=yes
  BROWSER_ONLY=no
  BOOTPROTO=dhcp
  DEFROUTE=yes
  PEERROUTES=yes
  PEERDNS=yes
  IPV4_FAILURE_FATAL=no
  IPV6INIT=yes
  IPV6_FAILURE_FATAL=no
  IPV6_AUTOCONF=yes
  IPV6_DEFROUTE=yes
  IPV6_PEERROUTES=yes
  IPV6_PEERDNS=yes

Many thanks in advance for any guidance you can give me.