Facebook PHP Sdk return redirect uri is required

Question

I am trying to authenticate using facebook php sdk but its returning error

The parameter redirect_uri is required

You can see in the url above the redirect_uri is present with its value.

Here is the code i am using

Config.php

<?php
//CONFIGURE YOU APP HERE
define("APP_ID","abcd");//REPLACE THIS WITH YOUR FACEBOOK APP ID
define("APP_SECRET","abcd");//REPLACE THIS WITH YOUR FACEBOOK APP SECRET
define("CALLBACK_URI","https://example.com/callback.php");//REPLACE THIS WITH YOU CALLBACK URL [This is where facebook will redirect user after login]
define("LOGOUT_REDIRECT_URL","https://example.com/close.php");//REPLACE THIS WITH URL OF YOU LOGIN PAGE    

/** APP CONFIGURATION END HERE **/


//NO NEED TO CHANGE BELOW ANYTHING 
require_once('facebook-php-sdk-v4-5.0.0/src/Facebook/autoload.php');//LOADS FACEBOOK SDK
session_start();
$fb = new Facebook\Facebook([
  'app_id' => APP_ID,
  'app_secret' => APP_SECRET,
  'default_graph_version' => 'v2.5',
  ]);
?>

login.php

<?php
require_once('config.php');//Loads configration

$helper = $fb->getRedirectLoginHelper();

$permissions = ['email']; // PERMISSIONS YOU WOULD LIKE TO ACCESS
$loginUrl = $helper->getLoginUrl(CALLBACK_URI, $permissions);

//$loginUrl =  '<a href="' . htmlspecialchars($loginUrl) . '">Log in with Facebook!</a>';
$loginUrl = htmlspecialchars($loginUrl);
header("location: $loginUrl");
exit();
?>

Answer 1

I had the same issue but I figured out my: $facebook = new Facebook\FacebookRedirectLoginHelper(URL) was different from what I had in my developers.facebook site.

Answer 2

The '&' within the URL is not accepted. Must be & instead.