Arduino UNO


I was looking for some guidance when I plug my arduino UNO board and 1 shield (Arduino Ethernet shield 2 With POE) I have no problems with the arduino regulator and seems to run with no problems.

When I disconnect the usb and connect the shield to POE connection it starts up and works but the arduino regulator its self the main shield burns up to point can't touch it, is this normal or is issue with my arduino regulator bored.

the only thing I am controlling is webserver through the arduino with a sensor ds18b20

I am only beginner for the arduino any help would be great

Thank you Robert