As reported on the evening of August 1 by an official Twitter account, there are problems with the automatic sharing of your tweets on Facebook. The problem, which some users had already noticed, is due to Facebook's choice to block some APIs following the Cambridge Analytica case. The API (Application Programming Interface) are – simplifying – programming interfaces that allow you to expand the functionality of a program, allowing customizations and interactions with other sites (in this case between Twitter and Facebook). Cambridge Analytica is the online marketing consultancy that, as was reported by many journalistic inquiries in March, misused a huge amount of data taken from Facebook.
The problems are therefore due to an update of the Facebook rules, which made automatic sharing from Twitter to Facebook impossible. Tweets can still be shared manually and it is possible that automatic sharing will work again in the next few days.
We've learned that Tweets and Retweets will no longer automatically post to connected Facebook accounts due to a recent Facebook update.
Don't worry, you have other ways to share a Tweet? Https: //t.co/fiwInkuyz7
– Twitter Support (@TwitterSupport) August 1, 2018