Have had Facebook authentication working great (not SSO) for the last 6 weeks within an IOS app however over the last couple of days it has broke. (no code, settings have changed)
When a new User logs in it comes up with the following error:
API Errorcode:100
API error description: invalid parameter
Error message: cancel_url URL is not correctly formatted
(if a user has already authenticated the app then it works fine)
If the user cancels the dialog and goes to log in again then it comes up with the permissions dialog straight away which leads me to believe the link is broken between the login dialog and permissions dialog, Facebook's side, as otherwise everything works as it should.
No code has changed and cannot find any reports of the above.
Can anyone shed some light on this?
It's a Facebook bug:
https://developers.facebook.com/bugs/280811108698311?browse=search_504cdd910488b0450000382
An alternative is to implement the single sign on which doesn't seem affected.
来源：https://stackoverflow.com/questions/12332909/cancel-url-url-is-not-correctly-formatted