HP Envy 6420e - Printer keeps going offline

[DaveFrancis]

I know this has been asked before but before I sent this printer back and ask for my money back I wondered whether there is a permanent fix out there for this issue.  I am on the latest firmware and the only way to get the printer back online is to yank the power lead!

At my wits end and just about to go back to a 5 year old Canon Pixma!

[Echo_Lake]

@DaveFrancis

Thank you for posting on the HP Support Community.
 

Don't worry as I'll be glad to help, to provide an accurate resolution, I need a few more details:

• Is your router dual-band enabled i.e., both 2.4GHz and 5GHz? If yes, make sure the dual-band has different SSIDs for 2.4G and 5G networks.
• What is the distance between the router and the printer?

This printer supports WPA encryption, check if the router is on the same encryption method. If using WEP or WPA-PSK+FT change it to WPA-PSK

In addition, perform a ping test to check the connectivity:

1. Click Applications > Utilities > Terminal.
2. type ping "IP address" and press enter

Wait until 10 pings have been performed and then press ctrl c on the keyboard and hit return. 
The results will appear. Share the ping test results.
 

The wireless status menu on your Mac should also give us quite a lot of information that would help us identify the issue. You can press and hold option-click the Wi-Fi icon and then use shift-command-5 to take the screenshot. Press the space bar when the icon turns into a camera. Share the ping test results and the screenshot with us.
 

Also, check with your Internet service provider if your router is able to forward 'Bonjour packets'.  Bonjour locates devices such as printers, other computers, and the services that those devices offer on a local network using multicast Domain Name System (mDNS) service records. The software comes built-in with Apple's macOS and iOS operating systems. 

And, also refer to the article: HP printer is offline or not responding By the end of the article you will be able to isolate the issue.
 

Hope this helps! Keep me posted for further assistance.
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