Suddenly couldn't print & can't rectify using HP Smart or Firmware Updater

[Di678]

What a palaver.... for some unknown reason after 2+ years of working perfectly the printer suddenly stopped working with my mac (OSX 10.14).The printer and mac are both connected to the same network but will not - no matter what I try- connect to each other  .... meanwhile all the other macs in the household continue to work.

I decided to delete the HP driver on my mac and re-install from HP website - when downloading found there was a critical firmware update too so I downloaded that and the HP Smart app.

Have now spent 2 very frustrating days trying to install these but being thwarted at every turn as the firmware wants to add the printer but because it can't connect to it-  it can't. The messages I've had include 'Device not reachable' , 'an error occurred while trying to reach/add the printer' , 'unable to verify the printer on your network' and 'unable to communicate with the printer at this time'.

All very wearing...  I've reset the print system on my mac, removed and tried to re-added printers (manually)several times, undertaken hard resets on the printer and ensured the printer itself has up to date firmware...

At my witts end now so can anyone help before I get the sledge hammer out? lol

[your_fix · Accepted solution]

Shut down or disconnect printer+laptop 

Unplug the router from outlet

Wait at least 30 seconds

Plug the router back into outlet -wait 3 minutes

Boot your laptop and wait for a network connection

Boot printer-wait for it to connect automatically to your router

Try to add it now in system preferences-printers and scanners 

[Di678]

Thank you, thank you, thank you for your solution - found your reply at c. 2am and followed your instructions straight away. However I thought it hadn't worked as I was unable to add the printer via system preferences, printers and scanners (none showed up).  After dwelling on it overnight I thought I'd have one more go using the HP Smart app and voilå it worked!!!!!   

Sanity now fully restored so thank you once again for your invaluable help.