ERROR -- omniauth: (facebook) Authentication failure - ruby-on-rails

Question

I'm getting the following error using the latest Omniauth Facebook gem:
ERROR -- omniauth: (facebook) Authentication failure! invalid_credentials: OAuth2::Error, :
My credentials are correct and i seem to hit facebook ok but the callback errors out.
Any ideas?

Answer 1

The problem I had was that my app was using an older version of the facebook API.
Omniauth-facebook uses a default API version, in my case 2.4 but my App needed a newer version because that is what it said in my Facebook Developer Console. In my case, all I had to do was to update the omniauth-facebook gem to version 4.0.
If you wish you can set the Facebook API version that you want to use instead of using the default like this (omniauth-facebook docs):
use OmniAuth::Builder do
provider :facebook, ENV['APP_ID'], ENV['APP_SECRET'],
client_options: {
site: 'https://graph.facebook.com/v3.0', # this is the example API version
authorize_url: "https://www.facebook.com/v3.0/dialog/oauth"
}
end
You can check which API verison your app is using by going to your facebook developer console.
You can read more about the omniauth-facebook gem API here:
http://www.rubydoc.info/gems/omniauth-facebook/4.0.0#API_Version

Answer 2

I had the same problem but specifying version didn't help me. I end up passing token_params: { parse: :json } something like below which resolved my issue :
Rails.application.config.middleware.use OmniAuth::Builder do
provider :facebook, Figaro.env.fb_appid, Figaro.env.fb_sec,
{ scope: 'email', token_params: { parse: :json } }
end
I have found the reference #174 comment

Answer 3

If you are not using the gem as a middleware directly and instead configuring your options in config/initializers/devise.rb (like the guide in Devise's wiki suggests), you can solve this issue by adding token_params: { parse: :json } to your config options.
So, in config/initializers/devise.rb:
config.omniauth :facebook, "APP_ID", "APP_SECRET", token_params: { parse: :json }
This problem is explicitly handled in Devise's wiki linked above (see section "If you are seeing something like Could not authenticate you from Facebook because “Invalid credentials”...)

Answer 4

Please try to put as many details as you can, try to be specific about your issue to understand the issue more deeply. It'll help to find out the exact issue and answers.
As you're not specific with your issue. I am putting here my answer which I got after so many tries and research.
MY ERROR
ERROR -- omniauth: (facebook) Authentication failure! invalid_credentials: OAuth2::Error, {"message"=>"Cannot call API for app 67878******** on behalf of user sa97**********", "type"=>"OAuthException", "code"=>200, "fbtrace_id"=>"8987987*********"}:
I was facing the above issue in a case if the Facebook user who is authenticating itself by Signing up with his/her details is only having the mobile number in his Facebook profile and NO EMAIL ID because my app is validating the email id should be present before creating any User object.
Because the same code is working fine with the users having the email id in the profile.
Although the Facebook error should be more specific, which saves the developer time to debug the exact issue.