Enable Serial Port 3 SKR 1.3 Marlin 2.1.2.2

I would like to configure Marlin to use UART3 on the default pins 0.0 and 0.1. Those pins go to E1 Step and E1 DIR which I am not using. When enabled in configuration.h and compiled I don't get any communication over port 3 and M43 shows them mapped to the E1 pins. I have disabled those pins in the pins.h file.
Serial is the USB
Serial 2 is the LCD
Serial 3 I want to map to UART3 using the default pins as seen in HardwareSerial.h

What am I missing that this is not working?