Because of how closely tied Coveralls is to GitHub for our GitHub users, Coveralls users will have experienced some follow-on issues from the GitHub incident yesterday: https://www.githubstatus.com/incidents/zjchv3zvfg50
For instance, we received a few reports yesterday of failed logins with the error message: “Sorry, there was a GitHub server error. Please try again shortly.”
In addition to this, it seems that other issues at GitHub related to the same incident may have caused other unusual behavior, including (temporarily) missing source files.