Unable to log in existing facebook user

Hi guys,

without changing anything, I’m unable to login with existing Facebook user.
I tried with another version of the same app here on backendless and it works good!
I tried to create a new user first, then logout and login again and it works.
Then I tried again with the first backendless app and it still doesn’t work!
In my console I’m getting this
“FAULT = Unable to register user. User already exists. <Unable to register user. User already exists.>”

My app id is 235A9D5C-40D9-D888-FF05-4CF678D82800

Are there ideas about this problem?

Hi Francesco,

This issue has been fixed in the latest release (3.0.8).
Please, update the latest lib, remove your user from your “first backendless app” and log in again.


Ok, i will try. But i have to remove all users logged in with Facebook?
I have some testers logged in with Facebook that are using my app, I need to remove each user?

First, try with one user - how this goes, then we investigate this situation.

My email: slavav@themidnightcoders.com
Maybe, you can send me your app Backendless AppId & secretKey and your FacebookAppID (which you’ve set in Info.plist):

And add my bundleId ‘com.themidnightcoders.FacebookLogin’ to your Facebook app:

Hope it let us to reproduce this problem.


I’m trying to solve this problem with Facebook…but now when new user signs up (default signup, no Facebook), I can see it in my console but I receive this FAULT message

FAULT = user credentials is not valid <backendless user credentials is not valid>
so I can’t go on this step…

It is a grueling problem guys…my app is ready to send in review but now I have to make some changes for this problem…:frowning:

After that fault message, I closed my app then opened it again: I can log in without problem into the app so I think that the problem is about registered user…

Problem solved…there are some differences in code since I updated to latest version of SDK