Facebook users have reported that they've been logged out of the app on their iPhones on Friday night.
While some thought it meant the site was down to start with, it turned out that many others experienced the same thing.
But when they went to log back in, the SMS two-step authentication was causing some issues, with people reporting the iOS app wasn't reconnecting.
Advert
Some said that the SMS codes were not being received, or were slow to send, meaning that others had to upload photos of their ID just to regain access.
A spokesperson for Facebook said: "We're aware that some people are currently having trouble accessing Facebook. We're working to get things back to normal as quickly as possible."
The social network even posted on Facebook about the issue.
The post read: "We're looking into reports of people being logged out and having to login again to access their Facebook accounts. We're working to resolve this issue as quickly as possible. Thank you for your patience."
Advert
People commented on the post, with thousands agreeing that it had happened to them.
One person wrote: "This happened to me and others I know, and changing the password was not easy afterwards."
Another pointed out some other issues with the app. They said: "Also look at the saved videos. When I clicked it says something is wrong. I had to click the three dots to view posts. There is also a problem in deleting the notification and clearing the search history. I had to do one by one clearing."
Someone else offered up some advice: "It was happening almost exclusively when looking at support notifications. Now, it's seemingly at random. Hope that helps the SRE team with the incident response."
Advert
Back in December there was an issue with the site's Messenger app, with thousands around Europe reporting that they couldn't log in.
According to Down Detector - a website that tracks user reports of problems with apps, services, and providers - the issues affected loads of users in the UK and mainland Europe.
At the time, 80 percent of those reporting a problem said they were unable to send or receive messages, whereas 20 percent of those who complained said they couldn't even log in.
Featured Image Credit: PA