Twitter says it lost 4 million users because of Apple iOS 8

The story has been corrected on the wire and the relevant paragraphs now read:

CEO Dick Costolo told Business Insider later that the one million users it lost couldn't get their passwords to work because of an encryption issue related to Twitter's integration with iOS.

On its earnings call, Costolo referred to the issue as an "unforeseen bug in iOS 8 as it relates to Twitter integration into the OS." He added that Twitter has a "great relationship with Apple."