Hi and welcome to JustAnswer,
Thank you for the question and your patience. Should you still need assistance for information purposes only...Initially, is this the first time the ink cartridges were attempted to be replaced?
Can you please (re-)try:
The only easy user doable checks then would be for possible dried ink or ink blobs or even lubricant or foreign matter in the area where the cartridges are mounted.
Additionally, ensure that the cartridges are vented and that the generalPrint Assembly area is clean of debris
Please post back results / observations of the above once tried.
Appreciate the post back.
If the electrical contacts of the cartridges as well as the contacts in the holder and general print assembly area are all clean, then it would appear to be a hardware issue.
Since these replacement have been done in the past and it would be highly unlikely for ALL print cartridges both new and old to be bad at the same time, then the cartridge mount itself or more particularly, the print head assembly would be highly suspect.
The prescribed next step would be to replace the print head.
Please post back how you would want to approach this and/or should additional information be needed.
I realize that the above information may perhaps be not what was expected. Unfortunately, there is no quick-n-easy fix and neither is there a workaround; sorry for having to be the bearer of bad news.