So I'm out of ideas, I don't know what to check or debug anymore, but on the exception I get this:
string(188203) "Facebook\FacebookAuthorizationException Object
(
[statusCode:Facebook\FacebookRequestException:private] => 400
[rawResponse:Facebook\FacebookRequestException:private] => {"error":{"message":"Error validating verification code. Please make sure your redirect_uri is identical to the one you used in the OAuth dialog request","type":"OAuthException","code":100,"fbtrace_id":"DqCCKoiN0r4"}}
[responseData:Facebook\FacebookRequestException:private] => Array
(
[error] => Array
(
[message] => Error validating verification code. Please make sure your redirect_uri is identical to the one you used in the OAuth dialog request
[type] => OAuthException
[code] => 100
[fbtrace_id] => DqCCKoiN0r4
)
)
[message:protected] => Error validating verification code. Please make sure your redirect_uri is identical to the one you used in the OAuth dialog request
[string:Exception:private] =>
[code:protected] => 100
I believed you have used different redirect_uri
in your facebook app settings and Oauth API code. thats why you got this error.
For facebook login you must set same redirect_uri into both place.