My printer keeps saying 'please insert card'

[12kmaxwell]

I have had no problems with my printer until yesterday. On the screen it says 'please enter card' and i have no clue what card it means? It is also now saying it is offline on the computer - i have a mac so went to system preferences removed the printer, restarted the computer and tried to add the printer again but no printer can be found, it is all plugged in.

Any help please?

[A4Apollo]

Hey there! @12kmaxwell, Welcome to HP forums.

I understand that your printer keeps saying you to insert card.

Kudos to you for trying out few steps reaching out to us.

Don't worry I'll try to help you out.

Please try the steps mentioned below.

This message has to do with the photo memory slot.  

Are you getting this error message on your printer or on your computer?

Try performing a hard reset on your printer and check if it helps.

Unplug all cables and memory cards from the printer.  Unplug the power cord, directly from the back of the printer while the printer is still turned on.
Unplug the other end of the cord from the power source.
If there is a power module on the power cord, disconnect one end and reconnect it.
After 60 seconds, plug the cord directly into a wall outlet ( not a surge protector or battery backup ).
Plug the power cord into the back of the printer.
The printer should automatically power back up.  If it doesn't, turn it on with the power button.
Try making a photocopy (if your printer is an all-in-one printer) before connecting any other cables to the printer.
Connect any other needed cables to the printer.

Also, refer this article to troubleshoot printer offline messages.

Let me know if this works!

Have a beautiful day ahead! 🙂