Printing Errors or Lights & Stuck Print Jobs

Hi, I have an OfficeJet 250 printer (bought in 2019) which has generally worked well. However it now won't recognise a newly-installed black cartridge.

I have always used genuine HP cartridges. The old cartridge ran out a couple of days ago, so I ordered a new one. When I went to install it today, first the printer would not start properly; on starting up, it would:
*announce "Remove and reinstall the indicated cartridge, making sure it is correctly installed",
*show a blue screen error B8777D74, then
*show a black screen with the message "There is a problem with the printer. Turn the printer Off, then On".

I cycled through this a few times, then unplugged the power, took out the battery, and tried again.

When it started again, it appeared to work OK, but indicated that the black cartridge needed to be replaced. When I installed the new cartridge (yes I did take the orange tape off...), it went through its checking process, then issued the error saying "Remove and reinstall the indicated cartridge, making sure it is correctly installed".

Since then, I have removed and reinstalled both cartridges numerous times, cleaned the contacts and the print head, cycled power on and off, unplugged it and removed the battery, re-powered the printer with every combination of 0, 1 and 2 cartridges installed.

No success.

It has now gone back to its original behaviour of instructing me to remove/reinstall the cartridge, followed by a blue screen error B8777D74, then the black screen saying "There is a problem with the printer. Turn the printer Off, then On".

In other words, I am £22 down on a black ink cartridge, with a printer that still won't work.

Help, please! 🙂