Users of Facebook and Twitter were left outraged after they noticed their old cross-posted content had discreetly been removed. It has now emerged that the cause of the vanishing content was due to Twitter’s decision to delete its app from Facebook.

Twitter took this course of action after Facebook stopped allowing cross-posts earlier this month, essentially making the app redundant. The removal took place after a recent API change that prevented Twitter users from continuing to automatically publish their tweets to their Facebook profiles.

The API change, which took place earlier this month prevents third-party apps from publishing posts to Facebook as the logged-in users. Permission for Twitter’s app was pulled as of August 1st. This move is part of Facebook’s larger overhaul and lock down of its API platform in the wake of the Cambridge Analytica scandal.

Users in the Dark

This change upset users who are more active on Twitter than Facebook. The function allowed them to keep their Facebook accounts active without the hassle of having to repost content.

According to TechCrunch, the deletion of the app took Facebook by surprise, as well as the fact that Twitter did not immediately tell the social media giant to restore the content. The company has said it is aware of the issue and is looking into it.

Affected users say that both Facebook posts and the conversations around those posts that took place directly on Facebook have also been removed. Many are concerned they will not be able to retrieve their old posts. As a result of the removal, their Facebook profiles have become quite bare. One user complained: “I run a small non-profit and had lots of important information cross-posted in that manner. It’s now gone.”

TechCrunch editor Matthew Panzarino, who was also affected by the removal, said the ability to share tweets to Facebook was a useful way to reach people who weren’t on Twitter in order to continue a discussion with different audiences, adding “it’s wild to have all of that content just vanish.”