Hi
I have an 8600 pro plus printer.
I put in new cartridges (non HP) and the printer was working fine.
I forgot to pull off the tape (breather port?) on the top of the black cartridge, and I think that is what caused it to print poorly.
Before I realized that, I removed and cleaned the printhead.
Now I get a notice that "there is a problem with the printer or ink system. "
I have unplugged, jiggled the printhead, re started and I still get this messages. Cartridges are new.