http://www.newsweek.com/facebook-messenger-down-not-working-1222681

Facebook users were realizing Monday that the Messenger service for the social media platform wasn't working. Users were reporting the issues to the website Down Detector just before 3 p.m. EDT. 

Hundreds of reports rolled into the website and other users were tweeting about the problems they were experiencing with the service. They were checking Twitter to see if other users were also experiencing messaging problems or if they were alone.