Well, that was speaking too soon! This month it had some issues that haven't happened before:
"Error: could not send data to print server. Job aborted."
That's understandable, the printer had a paper feed jam and stopped awaiting correction.
"Error: print server did not accept request. Job aborted."
Fair enough again, a knock-on effect of the above (the first message was within one print, the subsequent one was for a new print).
"Error: print server unreachable or specified printer does not exist."
For some reason, it seems the printer then took itself off-line (or maybe the OS decided it was off-line having not accepted too many transfers).
So far, not unreasonable. Once the jam was corrected and the job restarted, everything was fine again until:
"Error: host EPSON78163A is unknown."
That was in the middle of a print run, when everything seemed to be working fine! It just stopped for no apparent reason. Start the job again (without any other intervention) and it was fine for a while, and then "unknown" again. And after enough "unknown"s on the trot, "does not exist".