Manually choose a paper size that is loaded when you send the print.
It would appear that your Mac is for some reason seeing the printer as using ISO sizes, and i assume you are actually using American.
If it works when choosing Letter, then you could setup the driver manually via CUPS on the Mac.
Then it should be as simple as setting it to Letter via CUPS > Printers and selecting the queue for the specific printer here
Then choose Set default Options from the dropdown here
Then set the correct size here
Then click on Set Default Options which is hidden under the circle in the screenshot because I wasn't thinking
It will ask for a username and password at this point, and it will be for the Mac itself, not the printer.
I have a Xerox Phaser 7100.
I can print from my Old MacBook Pro (MacOS 10.9, Xerox 7100 driver 3.68.0) but NOT from my New MacBook Pro (MacOS 10.13.3, Xerox 7100 driver 4.14.0).
When I try to print from my New MacBook Pro I get the message "Load A3 plain tray 1" on the printer "screen" and that's that. Can't do anything otherr than press the red button on the printer to delete the print job. So, in effect, I can't print from my new MacBook Pro.
Very strange. Any ideas?