Pull the printhead back out and clean all the contacts both on the printhead and the carrier in the carriage. Use distilled water only and lint free cloth.
When you have the printhead out, put it in a plastic bag and seal the bag and shake the head really well.
Re-install the printhead, let the printer align it, then do a printhead cleaning.
After that do another diagnostic chart. Compare with original. If it's better, keep forcing ink through it - another nozzle cleaning, etc.
If the chart is the same or worse, you could have a bad printhead. Call your supplier for a replacement.