cannot print both sides

[Scon24]

will no longer print both sides keep getting “ paper too long to duplex”  i print from my ipad or iphone on smart app i am using A4 paper in fact same batch as i used when it would print double sided . I tried googling for advice and the virtual assistance which was hopeless  

I will be gratefull for any help

[Kumar0307]

@Scon24, Welcome to the HP Support Community!

Let us try these steps to resolve this issue:

Reset the printer

1. With the printer turned on, disconnect the power cord from the rear of the printer.
2. Wait at least 60 seconds.
3. Reconnect the power cord to the rear of the printer.
4. Turn ON the printer, if it does not automatically turn on.
5. Wait until the printer is idle and silent before you proceed.

Note: HP recommends connecting the printer directly to a wall outlet rather than a surge protector or a power strip.

Update the printer firmware

Click here to know different methods of updating printer firmware.

Also, check for any software updates on iOS devices.

Go to Settings > general > Update the software

Open the document you would like to print from the HP Smart app

1.) Launch the HP Smart app. 

2.) Touch the "Print Documents" tile and open your  PDF document. 

3.) Touch "Print".

4.) Touch on the grey line above the printer's name. Make sure 2-sided is set to "On".

Try printing.

If the issue persists, reinstall the HP Smart app.

Hope this helps! Keep me posted. 

Please click “Accept as Solution” if you feel my post solved your issue, it will help others find the solution.

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Have a great day!