Printer Brother DCP115C 8 months old Won't accept a new ink cartridge

High probability of a main board electronics failure and/or waste ink chamber is full. It is probably cheaper and quicker to just replace the machine

doesn't LC51M refer to Magenta(red) not Cyan(blue). on my J435W the colors goes as follows: BK Y C M LC71 Series cartridges. Maybe you have them switched around? just a thought.

Possibly at the time of release catrid black ink, color ink catrid position slightly annoyed and thought catrid sofwear printer cyan ink has been removed so that the request to install cyan. But it could also be due cyan ink has run out and ask to be replaced as new. Please check the contents of cyan ink may have run out, if still a full release catrid cyan and black, then attach it again, then go into maintance, and do head celean and do nozzle check or test printing

I contacted the Brother site, the support function there. Pursuant to what I found there, I unplugged the printer for ten seconds and replugged. The message display then told me that cyan was empty, and that magenta was near empty.

I installed a new cartridge in place of the empty cyan, and that fixed it.

That definitely sounds like the cartridge isn't registering properly. I would take the cartridge back to where you bought it and ask them to exchange it with a new one. This can happen from time to time.

If the printer was new out of the box, contact the manufacturer for a replacement cartridge. You can reach Brother here

7777 North Brother Blvd.
Bartlett, Tennessee 38133
1-877-BROTHER (877-276-8437)
901-379-1215 (fax)
9:00am to 8:00pm Eastern Time

i bought new inks and inserted them , when in fact its only the yellow inks is empty yet it sends me message that found no cartridges.. waah. this printer been with me for 8 years and had it clean last year only.. what to do?

Above link great.
If you have a newer print cartridge cart, look for the little window. I put a sticker over the little window on the Brother (innobella) LC38 cartridge cart and it worked great :)
Despite finding a fix for this problem, I think this is a rip off setting on the brother printers and I will never buy another Brother printer for this reason.

Do you use generic carts?
If yes try another cart (always best: original brother carts)

http://welcome.solutions.brother.com/bsc/public/us/ca/en/faq/faq_list.html?reg=us&c=ca&lang=en&prod=mfc210c_all&Cat=11

Unplug printer from power. Wait a minute. Take all carts out. Plug machine to power. mfc demands carts. Reinsert carts (have a look if they all filled with ink!!). If asked press 2 (No change) despite you use a new cart press 1 Yes cart changed.

Should work!

If you have used third party carts before you can't repair this problem due to the fact that the filter inside the printhead is clogged with particles. There is no chance to clean the filter. Sorry. Do use only dye ink. Pigmented ink is the printhead killer for brother printers!