It's been a bad week for Yahoo and users of its email services. Many users lost access to Yahoo email Monday night, and as late as Thursday the company was struggling to get the service restored and caught up delivering the backlog.
The problems are a black eye for Yahoo, which appeared to be turning itself around in the last year under the direction of CEO Marissa Mayer.
The outage was the result of a hardware problem at one of the company's mail centers, according to a blog post by Jeff Bonforte, the executive who manages Yahoo's email services. Yahoo has been overhauling its mail services this year and there have been periodic outages since October.