I also ran into this error, even after updating to version 19. To work around this issue, I used the advice given above. I modified the printer.cfg file to disable the fan tachometer for [fan], not ideal but better than no print.
This file can be access through the web portal (found by going to the printer’s IP address in a web browser) or by access through the Device page in Orcaslicer. Go to Device → Machine and scroll to the printer.cfg file. In here you will be able to comment out the lines shown in the image above.