This printer is clearly marketed as only accepting HP original cartridges and if you accepted the terms of HP+ when setting it up, you also confirmed you agreed to that limitation in exchange for getting a longer warranty and other perks that do not apply to Non + printers. You saved money buying the + version but exclusive use of HP OEM cartridges was part of the deal.
As per the disclaimer here https://www.hp.com/ca-en/shop/product.aspx?id=1w2y8a&opt=b1h&sel=prn
Refilled OEM cartridges that maintain HP original electronic chips will work.