Check PoE Budget: Ensure the PoE switch or injector has enough power budget to support all connected devices. In a basic PoE power supply system, the major components are the power sourcing equipment (PSE), the powered device (PD), and the PoE cables. Any idea? (just curious) Is POE enabled in the config of the switch? Maybe something went. This document describes how to troubleshoot Power over Ethernet (PoE) on Catalyst 9000 PoE-capable switching platforms. However, when PoE fails, it can disable critical infrastructure like IP phones, wireless access points, and security cameras.