I have an Epson wireless printer & Google Wifi router. My printer stops working wirelessly whenever it sits Idle for a few hours. It shows as offline in Windows, Google Cloud Print, and the Epson iPrint app. If I power cycle the printer it reconnects to the network and everything works fine (until nit sits idle again)
I've contacted Epson support and they say this is an issue with my network. I changed the printer to a static IP address but it hasn't helped. Google Wifi support checked out my network settings and say everything look ok there and there's nothing that would cause a device to drop from the network.
Most recently Epson says:
There is no setting on the printer itself to drop off the network or remain on. This issue is typically related to switches and routers that are not properly configured to handle “Wake On LAN” (WOL) packets.
Please contact the ISP or manufacturer of the router for any firmware updates. Also check if there are any settings that may block communication to the printer such as “Quality of Service” (QoS) or firewall settings.
Google says to contact my ISP to see if there's a setting for QOS or WOL.