I bought a MFC-L2750DW and a TN-760, both brand new, sealed in a box, but the printer will not recognize this toner cartridge. I have two other toner cartridges, they both work 100%. But this TN-760 does not work. I replaced the drum unit, TN-760 still doesn't work. I put the TN-760 into an almost new DCP-L2550DW, TN-760 still doesn't work. Both new printers display the same error message - No Toner. Install Toner Cartridge. This really sucks, this is very expensive garbage!