Numerous developers have posted screenshots showing access to other users accounts on Twitter. One user appears to have been logged into BlackBerry's official account.
Holy shit every time I hit sign out on iTunes Connect it signs me in as a different random user: pic.twitter.com/l2km2nNRBS— Mo Bitar (@bitario) January 29, 2015
Most definitely was auto logged in to a blackberry account on iTunes connect somehow... This isn't mine! pic.twitter.com/S9lujDno95— Bay Phillips (@bayphillips) January 29, 2015
To find out when the issue is resolved, developers can watch Apple's System Status page.