Arduino Mega and Serial LCD?

I’ve got an Arduino Mega 2560 and a Serial LCD (twig) from Seeeduino that I cannot get to work. The LCD works very well with any other board I have tried such as the UNO or the pro with no problems at all. The Mega seems to not communicate with the screen. I have tried many different I/Os. I am just using the basic “Hello World” example code to test this out.
Any help would be greatly appreciated.
Thanks, Nick

You can refer to … b#Cautions

That’s it!
Thank you.