"We're working to resolve the issue as soon as possible", a Facebook spokesperson wrote in an email to Mashable.
Several of Facebook's products are suffering partial outages, affecting users globally. We can confirm that Facebook's Workplace and Work Chat apps are also affected by this outage.
Some users complained that they were unable to connect to the sites at all, while others reported being unable to tag people or post comments on Facebook posts. Other users were reporting that they couldn't log in to the app at all to even try posting.
According to The Verge, Messenger couldn't load at all on the desktop, but the mobile app was working.
Instagram is also owned by Facebook Inc.
Backed forces launch assault on IS group's last Syrian enclave
The numbers have flummoxed the Kurdish-led forces and bogged down their offensive to finish off the once sprawling proto-state. It was not clear Sunday how many fighters and civilians remained in the half-mile-square pocket under ISIS control in Baghouz.
"Facebook for personal use is fine - but what happens when we rely on large companies such as this to provide business services?" she said.
Right now, news outlets aren't sure how you're getting to this article because Facebook drives so much traffic.
For Facebook, DownDetector.com states that out of reported problems, 34 percent can't log in to their accounts, 33 percent can't access their newsfeed and 32 percent are experiencing a total blackout.
Instagram has not issued a message through Twitter.