Welcome to HP Support Forums. 🙂 I came across your post and would like to help.
I understand that you have an HP ENVY 4520 All-in-One Printer and it displays an error message stating "incompatible ink cartridge." Due to this the printer is unable to print.
I would like to know the following information to assist you better:
Are you using original HP cartridges or refilled ink?
Di you happen to replace the cartridges recently?
Meanwhile, below is the list of compatible cartridges for your HP printer:
I recommend you to perform the following steps to isolate the issue and arrive at a fix:
Disconnect the power cable from the printer while the printer is still ON.
Disconnect any other cables if connected the printer.
Press and hold the printer’s power button for 15 seconds.
The printer should be directly connected to the wall outlet and not to a surge protector. Reconnect the power cable to print and the printer should power ON by itself. If the printer doesn’t power ON then please manually power it ON.
Also, please perform the steps as described in detail from this link which is known to fix the incompatible cartridge message.
I sincerely hope this fixes the issue. Please let me know the outcome. Good luck! 🙂