My computer says my printer is offline but it isn't - It's online on a different subnetwork

[RichTorb]

My HP laptop computer is connected to network 192.168.1.1 via wireless (it's IP Address is 192.168.1.59).  I have two HP Envy 4520 printers.  One printer is connected wirelessly to the same network (it's IP Address is 192.168.1.155).  The second printer is wirelessly connected to a subnetwork (192.168.4.1).  The second printer’s IP Address is 192.168.4.45.  The subnetwork (192.168.4.1) is connected to the primary network (192.168.1.1) via an Ethernet connection (its IP address is 192.168.1.254 on the primary network).

The HP Smart Application Home Page on my laptop computer shows Printer 192.168.1.155 as being online and so do all my Office applications.  I can print to this printer from all my laptop computer’s Office applications.  The HP Smart Application Home Page on my laptop computer shows Printer 192.168.4.45 as being offline and so do all my Office applications.  I can't print to this printer from any of my Office applications on my laptop computer.

If I go to the HP Smart webpage https://www.hpsmart.com/us/en/ucde/my-printers it shows both printers as “Subscribed to Instant Ink” and “Connected to the Internet.”

I have an HP desktop computer on the subnetwork (it's IP Address is 192.168.4.42).  The HP Smart Application Home Page on this desktop computer shows the subnet printer (192.168.4.45) as being online and my Office applications on this desktop computer also show this printer as being online.  The HP Smart Application Home Page on this desktop computer also shows the primary network printer (192.168.1.155) as being online and so do all my Office applications.  I can print to both printers (192.168.1.155 and 192.168.4.45) from my desktop computer located on the subnetwork.

I can also successfully print to both my printers via Email using the HP ePrint function.

I recently tried manually setting the wireless address on my second printer to 192.168.1.215 so that it is connected to the primary network.  This doesn’t fix the problem detailed above (printing on my second printer (192.168.4.45) from my laptop.  It actually makes things worse because for some unknown reason this causes the second printer to become disconnected from the internet.  This means my Instant Ink subscription is no longer functional.  Multiple restarts of the second printer do not make any difference and it remains disconnected from the internet until it is allowed to reconnect to the subnetwork via DHCP.

Why can’t I get both computers to successfully send print jobs to the printer of my choice?