This happens on the newest Samsung android phone, probably on older devices too, I just don't have them. Facebook is not installed. First login using webview happens successfully, webview popup shows up and everything works. However, consecutive logins do not work. Basically, webview that notifies you that you have already given permissions to this app shows up, user clicks ok, nothing happens in the app. No error messages, nothing! This is in production, so it's kinda urgent.
This scenario does not happen on iPhone. Sometimes authentication fails when Facebook redirects back to the app, but I just retry a couple of times in the code and it's good enough.
Any help is appreciated,