Thanks for reaching out to us with your report, @Kjartan_Bergsson!
May I ask that you please provide a brief description of your current setup using this link as a guide.
Make sure to describe your network configuration/topology, including any networking hardware currently in use, so we can have a clear understanding of how your devices are communicating.
Since updating have you tried power cycling your Core machine, networking hardware, and endpoints?
Do you have any non-networked devices available? Are you able to play to those succesfully?
Thanks,
Dylan