You can easily establish wireless connection with the wireless HP Officejet Pro 8720 printers or extenders with the WPS button..

1. HP OFFICEJET PRO 8720 PRINTER WIFI
The HP OfficeJet Pro 8720 printer is an all-in-one printing machine. The
printer is designed for small and mid-level offices because of the
convenience in quality and productivity. The printer boosts with
automatic 2-sided (duplex) printing and high-speed outputs.
Productivity includes the ability to print documents at amazing speeds
(22 pages per minute in black and 20 pages per minute in color). The
machine is equipped with a standard 250-sheet tray and comes with an
additionaltray included.
With all these amazing features the printer possesses, there are some
problems you might encounter wirelessly. You will face some scenarios
where you will not be able to get the HP OfficeJet Pro 8720 printer
connected to the Wi-Fi, and such issues can be sorted out.
Now, there can be quite a few reasons behind the issue. Here are some
pointers to work on before you go ahead with the troubleshooting
methods.
 Check if the HP printer is connected to the wireless network.
 Check if you have changed the password for the wireless network
recently; reconnect the printer to the network.
 Do a reset to your router: Unplug the router from the main
power source, wait for 2-3 minutesand then plugit back in.
 Do a reset to your HP printer: Remove the power cord of the
printer from the power source, wait for 2-3 minutes and then plug
it back in.
 If the Wi-Fi signal appears to be weak, make sure to move the
printer to a proximity range around the router so it can have a
strong and stable connection.
 Make sure there are no metal objects or electronic devices near
the HP OfficeJet Pro 8720 printer or the router.
Print a copy of the network configuration page to see the error you are
facing:
 Makesure the printer is turned on.
 Have a coupleof papersloaded.

2.  Tap on the Wireless icon.
 Select the Settings option.
 Tap on Print Reports option.
 Select either the Network Configuration Page option
or Wireless Test Report option.
If you still have a problem with connecting the HP OfficeJet Pro 8720
printer to the wireless network, here are the troubleshooting steps.
METHOD1: USE THE HP PRINT& SCAN DOCTOR UTILITY
 You can download and install the HP Print & Scan Doctor utility
from the official HP Supportpage.
 Select the HP OfficeJet Pro 8720 printer from the list. Click
the Retry button if the printer is not listed.
 Based on the Wi-Fi issues you are facing with the printer, follow
the on-screen commandsin the tool.
 If there are no issues with the printer, you will see a green tick
that indicates the printer has passed the diagnosis and is now
ready to connect to the Wi-Fi.
 If there is an issue, the app would display the issue specifics and
recommend troubleshooting it. Follow the prompts as displayed
to resolve the issue.
METHOD2: THE HP OFFICEJET PRO8720 PRINTER IS OFFLINE
Windows:
 Open the Settings window (Windows+ I).
 Click the Devices option.
 Select the Printers & Scanners option.
 Click the HP OfficeJet Pro 8720 printer and delete the pending
printjobs.
 Click the Printer tab, make sure the checkbox "Use Printer
Offline" is not ticked.
Mac:
 Open the HP Smart app (available for download from the Mac App
store).
 Once the HP Smart app is open, click the Printers option.

3.  Click the Diagnose & Fix option.
 Click the Start button in the dialog box.
 Once the diagnosis is complete, click the Done button.
Bringing back the Online status will have the HP OfficeJet Pro 8720
printer connect to the wireless network.