Probably because nobody plays it anymore. I doubt Rockstar still gives it much support.
That doesn't make sense. A heck of a lot more people (would) play Red Dead Redemption online instead of Grand Theft Auto IV online which still works fine (strangely enough).
I always had troubles playing RDR online, it has to bee something wrong with R* servers because I can play everything else without care. The fact that almost every piece of manpower is probably focused on GTAV is not helping either.
Too bad because, whe you can play it, is one of the best MP out there.
Rock Star Games really needs to come out with a sequel to RDR and bring it back bigger than the original.
If we took just five minutes, to recognize each others beauty, instead of attacking each other for our differences .............