Players had trouble logging into the game since around the middle of Sunday. Since then the entire website went offline. The LOTRO Facebook page hasn't been very people, relaying the standard IT response of they know about the problem and there is no ETA when the game will be back up.
What is known is that their vendor (Pando Media Booster) who supports downloading and updating the game, went out of business Aug 31, as seen on the Wikipedia page. This is also supported by Turbine on the LOTRO Facebook page saying they were having problems with their vendor. Who knows when the game will go back online.