Insufficient Power - First, check the powering switch, its power management configuration, and if it's working properly. When a problem occurs with PoE, in most cases, the error symptom can be simply shown as the PoE switch not providing power, and the powered devices will stop working. The cause of failure may be attributed to many factors, including hardware device factors and software factors. Many times, this issue is seen during the power maintenance or power. Power over Ethernet (PoE) simplifies device deployment by delivering both data and power over a single Ethernet cable. I am not getting any link, or power when I plug in PoE RJ45 cable.