I ran into this issue with a FS-C5300, but I think this will be an issue with most any printer or print-system connected by network interface.

The customer could print if the PC was freshly started. If the printer went into sleep mode, it would then fail to deliver the print job from the PC. There is only a single PC and this printer on the network (both connected to a regular router for the internet). Could ping the printer fine, and browse OK with a web browser. Customer said the they would have to restart the PC after waking the printer by pushing buttons on panel in order to start printing again.

Turns out AVG internet security firewall was blocking the print jobs. Disabling the firewall allowed all print jobs in queue to get delivered. I was unable to figure out which firewall rule exactly was stopping printing, but since this printer was sitting right next to the PC anyhow, I took it off the network and connected with USB instead.

AVG's almost worse than having no protection - it gives a false sense of security.

It's way cheaper to buy a decent security package than it is to suffer the consequences.

Have been using this one for a while seems to be ok so far
microsoft free antivirus

I've had this before. I loaded the latest firmware and the sleeping issues went away. It has something to do with the networking system not waking the machine up when the job came through. Has work flawlessly since.

also check the customer network adapter, it could be set to sleep also. this can be disabled to keep the adapter active in the adapter property settings power management.