Problem: Apple devices (2018/2015 15" MacBook Pros running 10.15.5, 2018/2020 iPad Pros running iOS 13.5) no longer print wirelessly to HP LaserJet Pro M452dw.
Configuration: 2.4 and 5 GHz networks run through the Netgear C7800 cable modem. One2018 MacBook Pro and an HP x360dt with Windows 10 Pro 64-bit connected via Gig-E to the cable modem via 2 meter Cat 6 cable. HP printer is connected to 2.4GHz net (printer also has a Gig-E connection but it is not connected). iPad Pros and 2015 15" MacBook Pro connect wirelessly to 5GHz network. The networks have the same network name except the 5GHz has "-5GHz" appended to the network name.
What's been tried: Windows laptop prints to the HP in every possible configuration; laptop connected wirelessly or wired ethernet and printer wireless as well as the printer connected via cable and laptop both wired and wireless. No issues. I have also worked through all possible router settings with Netgear support including changing channels and factory reset and reconfigure the router.
iPad Pros will print wirelessly when connected to the exact 2.4GHz network. Not when connected to the 5GHz network and not when the printer is connected via ethernet cable.
2018 MBP will print when it is connected via wired ethernet AND the HP printer is connected via wired ethernet. When the MBP is connected via ethernet cable and printer is connected to a wireless network the Mac can see the printer, see the status, toner levels, configuration, open HP utility and connect, and can open the printers web admin interface and make and save changes. I can do absolutely everything necessary to manage the printer. What I can't do is print anything.
2015 MBP will print only when the MBP and the HP printer are on the same wireless network.
I've deleted the printer from all systems and reset the printing systems. Re-installed using the HP Easy Start Utility. It sees and configures the printer w/o problem until it gets to printing a test page. At which point the test sits in the queue waiting on the printer.
Since every non-Apple product can see and print to this printer no matter how the printer is connected (wireless or ethernet cable) I don't think it is a router configuration issue, but there may be something that needs to be set in the Netgear router I'm not aware of.
I can ping the printer from the Mac:
Last login: Mon May 25 17:08:27 on console
Xxxxxx@Davids-2018-MacBook-Pro ~ % ping 192.168.0.27
PING 192.168.0.27 (192.168.0.27): 56 data bytes
64 bytes from 192.168.0.27: icmp_seq=0 ttl=255 time=4.927 ms
64 bytes from 192.168.0.27: icmp_seq=1 ttl=255 time=5.494 ms
64 bytes from 192.168.0.27: icmp_seq=2 ttl=255 time=39.107 ms
64 bytes from 192.168.0.27: icmp_seq=3 ttl=255 time=5.113 ms
64 bytes from 192.168.0.27: icmp_seq=4 ttl=255 time=13.047 ms
64 bytes from 192.168.0.27: icmp_seq=5 ttl=255 time=17.061 ms
64 bytes from 192.168.0.27: icmp_seq=6 ttl=255 time=8.251 ms
64 bytes from 192.168.0.27: icmp_seq=7 ttl=255 time=7.449 ms
64 bytes from 192.168.0.27: icmp_seq=8 ttl=255 time=4.877 ms
64 bytes from 192.168.0.27: icmp_seq=9 ttl=255 time=10.505 ms
64 bytes from 192.168.0.27: icmp_seq=10 ttl=255 time=4.708 ms
^C
--- 192.168.0.27 ping statistics ---
10 packets transmitted, 10 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 4.708/10.032/39.107/9.163 ms
But any print job just hangs in the queue. It may print a page in a few hours or so.