Facebook says some users were logged out of their accounts unexpectedly Friday due to a “configuration change,” and the issue has been fixed as of Saturday morning.

“On January 22, a configuration change caused some people to be logged out of their Facebook accounts. We investigated the issue and fixed it for everyone earlier today. We’re sorry for the inconvenience,” a Facebook company spokesperson said in an email to The Verge.

The problems began late Friday ET, with users on the r/Facebook Reddit board reporting they were receiving “sign in” prompts from their Facebook apps, but they had not signed out.

Engadget found that iPhone users appeared most affected by the log-out issue, noting that users of Facebook’s iOS app were having difficulty logging back into their accounts when using two-factor authentication. Most were able to log back in, but the authentication codes needed were taking a long time to reach users.