Printing black boxes everywhere

I have an Epson EcoTank ET-2800 printer. Recently, I used a printhead cleaning kit because the yellow ink was not printing. I also used the kit to try to remove any air bubbles, as I was noticing missing lines in my prints. I printed a test sheet after using the cleaning kit and only two colours dispensed (magenta and cyan). So then I ran a power cleaning cycle which resulted in this:

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The attached photo shows the result of a nozzle check. The first time I run a nozzle check, the page comes out completely blank. The second time, it prints these colour blocks.

Is there any way I can fix this?