Facebook login unavailable - do not logout

If you login to the service using Facebook, please do not log out unless absolutely necessary. This issue will be marked as resolved once it is safe to do so again.

Otherwise, request a password reset here :

Password reset form

And log in with the your email and the generated password.

edit : This affects all clients (apps and web).

Removing Facebook authentication altogether in the future is definitely under consideration now there are way better options (Apple ID on the iPhone app, for example.)

A little update - this is still not reinstated, so original warning stands.

It appears likely that an issue with the latest Android build's Facebook login has caused Facebook to turn off access for Web and iOS weirdly. (Thanks Mark Z!)

A new Android build will be being submitted ASAP now the probable cause of their actions has been figured out. At which point a request to Facebook to review their decision will be sent....so this is definitely at the very least a few days away from resolution.