These printers are going to be the death of me

Latest problem: one just keeps giving me errors about missing toner cartridges. Apparently it thinks that there are no cartridges installed even though they are.

Have had this issue before but only one cartridge at a time and is usually solved by reinserting the effected cartridge.

This time its all the cartridges and nothing is helping.

Desperately seeking ideas (or a close bin!).