It seems that your switch has a hardware problem with some of its network interface controllers and probably needs replacing. Sorry to bring bad news but if a POST fails with an error such as this (PHY loopback failed) and does not go away even after completely turning off the switch, waiting for a couple of minutes and then plugging it back into power with all devices disconnected from it then it's time to replace it.
Best regards,
Peter
Getting Started
Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community:
