Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.
'Service error' generally means something severely wrong, I'm sorry to say.
It would help if you had stated what maker, and model #, of printer you have. Please Reply letting me know.
Try turning the printer Off. Unplug it from the power too.
Leave it that way, unplugged from power, for 1 hour or longer.
After that interval plug it in again, turn it On, see if the service error is cleared.
Generally speaking a Service Error is accompanied by a code or other more specific indication. Does your printer show one? if so, let me know, please.