Magento – Rest API 403 Access Denied

I can give you workable example:

System / Web Services / REST Roles

    Role info: 
Role Name: admin
Password: 123123
    Role API resources:
Resources access: All
    Role Users:
I have assigned admin user

System / Web Services / REST Attributes / Select {Admin}

Resources access: All

System / Web Services / REST OAuth Consumers

My magento url is http://mg1910.local.dev/

My http://mg1910.local.dev/oauth_admin.php is following:

<?php

/* live server */
$host = 'http://mg1910com.local.dev/';
$consumerKey    = '7e14cd85d05456c3e4de9e3c5c5f61e4';
$consumerSecret = 'f8aab713fa50504f0fac99d564ecaf7a';
/* << live server */


$callbackUrl = "http://mg1910com.local.dev/oauth_admin.php";
$temporaryCredentialsRequestUrl = $host . "oauth/initiate?oauth_callback=" . urlencode($callbackUrl);
$adminAuthorizationUrl = $host . "admin/oauth_authorize";
$accessTokenRequestUrl = $host . "oauth/token";
$apiUrl = $host . "api/rest";

session_start();
if (!isset($_GET['oauth_token']) && isset($_SESSION['state']) && $_SESSION['state'] == 1) {
    $_SESSION['state'] = 0;
}
try {
    $authType = ($_SESSION['state'] == 2) ? OAUTH_AUTH_TYPE_AUTHORIZATION : OAUTH_AUTH_TYPE_URI;
    $oauthClient = new OAuth($consumerKey, $consumerSecret, OAUTH_SIG_METHOD_HMACSHA1, $authType);
    $oauthClient->enableDebug();

    if (!isset($_GET['oauth_token']) && !$_SESSION['state']) {
        $requestToken = $oauthClient->getRequestToken($temporaryCredentialsRequestUrl);
        $_SESSION['secret'] = $requestToken['oauth_token_secret'];
        $_SESSION['state'] = 1;
        header('Location: ' . $adminAuthorizationUrl . '?oauth_token=' . $requestToken['oauth_token']);
        exit;
    } else if ($_SESSION['state'] == 1) {
        $oauthClient->setToken($_GET['oauth_token'], $_SESSION['secret']);
        $accessToken = $oauthClient->getAccessToken($accessTokenRequestUrl);
        $_SESSION['state'] = 2;
        $_SESSION['token'] = $accessToken['oauth_token'];
        $_SESSION['secret'] = $accessToken['oauth_token_secret'];
        header('Location: ' . $callbackUrl);
        exit;
    } else {
        $oauthClient->setToken($_SESSION['token'], $_SESSION['secret']);
        $resourceUrl = "$apiUrl/products?limit=3";
        //$oauthClient->fetch($resourceUrl, array(), 'GET', array('Content-Type' => 'application/json'));
        $oauthClient->fetch($resourceUrl, array(), 'GET', array('Content-Type' => 'application/xml', 'Accept' => '*/*'));
        $productsList = json_decode($oauthClient->getLastResponse());
        echo "<pre>";
        print_r($productsList);
    }
} catch (OAuthException $e) {
    print_r($e->getMessage());
    echo "<br/>";
    print_r($e->lastResponse);
}

As you can see my script receive 3 products.

Try having only one space between 'Bearer' and the token. That worked for me (two spaces did not).