L26500 Printhead not firing

[mams4s]

L26500 having problem of Printheads, all PH are new , but after 15-20ml , it stops firing now i have problem with yellow Ph and magenta ph both are not firing, i cleaned many times but still not opening, i am not understaning where is the problem, do i need to replace ink tube for this problem. or what.

suggest please.
thanks

 

[chester215]

We have a L26500 and have had a problem with new print heads not working correctly right out of the box.
It has happened as recently as last month.
HP does print an expiration date on the box of the print heads, I don't know if it makes a difference but it is there.
When it happens I call HP tech support and they always have sent a replacement head overnight.
If they replace the print head, save the old one because they send return packaging. We have had to go dumpster diving to find ones to send back because they were thrown into the trash.

It could be something else but don't assume that all new HP print heads are good right out of the box.