LaserJet Pro MFP M479fdw won't wake up to print

[bajhn]

Our HP M479fdw sometimes won't wake up and print, and the only thing that gets it working is to power it completely off and reboot it. The last time this happened, I tried to login to the web administration page, and the only things that loaded in the browser were the thin blue line and white background of the page. The printer still responded to ICMP pings. My wife sent two print jobs to it from her Windows 10 computer, and they processed through the Windows print queue and disappeared, but nothing came out of the printer. There were no  recent events in the event log (the last being a fax error from Feb. 28th), and there is nothing at all in the job log even though it's enabled.

Our setup is this: the printer is cabled to a gigabit switch. It gets its address via DHCP, and the router has a reserved address for it, so it is effectively static. Wife uses Wi-Fi to get to it, and my desktop computer is cabled to the same switch along with my work VPN equipment. I had a good connection on the VPN, and the ping from my desktop computer also demonstrates that we had IP.

The printer's firmware version is CLRWTRXXXN002.2247A.00, which is the latest firmware offered by HP. All of the toner cartridges have plenty of toner, and there are no errors reported. What do I need to look at next?