Before you do anything else - check your inks - physically.
I did the open/shut thing over and over again to no avail and then found a fix on another site posted by a person calling themselves Colas (to whom I am now most grateful)!
He suggested that despite the display showing his inks were full, when he checked one or two of them were empty. Presumably a problem with the chip - which I assume would be more common if you’re using compatibles rather than genuine (I use compatibles).
I did the same - found this to be the case - replaced them and now my printer is working again. I am keeping my fingers cross that this isn’t a temporary fix, but so far so good.
Good Luck!