I think it must be a 3550 issue with toners, I sell many tn247 toners, the newest microchip on the cartridges, have the same issue with a customer, the printer does not tell you which one has failed (so frustrating)
last Friday it happened after only a few weeks with the set in the printer which had been working perfectly, found it to be black toner chip that printer would not accept, one week later, comes back again with the printer, this time I find it to be the cyan, one day later, again NO TONER, the toner reset does not work if the printer is not registering all 4 toners, have had to order brother tones sadly as have no OEM chips to put on the toners, very frustrating as normally such a reliable remanufactured toner series