It won't surprise you to hear the cause. Facebook just altered its developer frameworks in the name of improving data privacy, and the social network has confirmed in a statement that these problems were "part of the changes" and that it's "working with Tinder" to fix the problem. We've asked Tinder for comment and will let you know if it can share more.

There isn't word of other services breaking as a result of Facebook's changes, but don't be surprised if other services struggle for a while as a result. Regardless of what happens, the incident underscores one of the problems with the ubiquity of Facebook as a sign-in option: it's very convenient when everything works, but even a minor tweak to Facebook's code can break entire services.