LaserJet constantly losing Wifi Connection

[buckthorn]

After working flawlessly for several years, this Laserjet has developed a very bad habit of losing its wifi connection while in "sleep" mode. The print utility says the printer can't be found or is offline, and the control panel on the printer shows a warning+exclamation point icon overlaying the wifi icon. I've tried resetting the wifi setup several times, including re-entering a long WPA2 password (which is a real pain). That usually works. Sometimes (but not always) rebooting the printer works -- and sometimes it takes several reboots.

What would cause the printer to keep losing the wifi connection? And if it does, why wouldn't a simple reboot immediately restore the connection? We don't print all that frequently (maybe a few times a week), so lately every time we do want to print, we have to troubleshoot the wifi connection, which is ridiculous.

Signal strength is not an issue; the router and wifi access point are three feet away from the printer.

While the printer gets an IP via DHCP, we  -- all MacBooks running MacOS 10x (Catalina) -- print via Bonjour. We don't use Wifi Direct printing, which is disabled.

[Valsimot]

For testing purposes can you create guest wireless without a password and connect the printer to that network to see how will it lose connection?

[buckthorn]

After it dropped off again, I switched the printer over to our guest network last night. I'll give it a few days and report back. I'm still puzzled as to why only this particular device would drop off the regular network; it doesn't happen with any of our other devices, including a NAS and an old "webbox" (running Windows) that  manages our solar panel data. depending on what happens with the guest network test, I may assign the HP a permanent IP instead of using DHCP. Perhaps there's an issue involving the printer's going to sleep and losing its IP. Printing a printer network test report (when it's connected, that is) indicates no problems.

"For testing purposes can you create guest wireless without a password and connect the printer to that network to see how will it lose connection?"

[buckthorn]

OK, so as expected, changing the wireless network had no effect. The printer again dropped off the network, and was not ping-able. I've moved it back to the regular wifi network, and gave it a manually-assigned IP (but still on DHCP). But this is pretty much a shot in the dark.

It's hard to believe that this is a unique case. It appears to me that something is happening during sleep mode that causes the printer to lose its network connection, or prevents it from regaining it upon waking up.

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(Edit)
I decided to remove DHCP from the equation and instead manually assigned the printer and IP outside the DHCP range. I'll report back in a few days.

[buckthorn · Accepted solution]

Moving the printer off DHCP to a fixed IP seems to have solved the problem.