Battle.net is experiencing issues with its authentication servers that is causing sign in problems for some users, according to an announcement on the U.S. Battle.net support page.
"We are aware of an issue that is affecting our authentication servers which may result in slow or failed login attempts," the statement reads. "We're investigating the cause and will provide updates as they are available. We appreciate your patience."
The warning is not apparent on the European support page. We have reached out to Blizzard for further information and will update this article accordingly. Xbox One users are also currently experiencing problems signing on for Xbox Live.