altium designer - Could not find port 'PA0' on model 'tm4c1294_01' for pin 'PA0'
Your 'Designator' fields on the schematic symbol pins have to agree with the pads on the footprint. Otherwise, how would the program know where the pin numbers are on the footprint? 

You can make the 'Display Name' whatever you like- it's just for human use. 

Where you have PA0 etc. one would normally have the physical pin number, matching exactly the pin numbers on the footprint. 

You can fix it by editing each of the schematic pins, and that should do it, if your footprint is numbered correctly.