If your HP printer is not recognizing ink cartridges, several factors may be at play. Firstly, ensure that you have installed genuine HP ink cartridges compatible with your printer model. Examine any packing or protective tape that might be blocking the cartridge contacts. Clean the cartridge and printhead contacts gently with a lint-free cloth to remove any dirt or residue. Verify that the cartridges are securely snapped into place. Additionally, confirm that the ink levels are sufficient.