diff --git a/lib/oauthlib.php b/lib/oauthlib.php
index 7f5ea64fe08..6fc448312ea 100644
--- a/lib/oauthlib.php
+++ b/lib/oauthlib.php
@@ -264,6 +264,8 @@ class oauth_helper {
         $this->sign_secret = $this->consumer_secret.'&'.$secret;
         $params = $this->prepare_oauth_parameters($this->access_token_api, array('oauth_token'=>$token, 'oauth_verifier'=>$verifier), 'POST');
         $this->setup_oauth_http_header($params);
+        // Should never send the callback in this request.
+        unset($params['oauth_callback']);
         $content = $this->http->post($this->access_token_api, $params, $this->http_options);
         $keys = $this->parse_result($content);
         $this->set_access_token($keys['oauth_token'], $keys['oauth_token_secret']);
diff --git a/repository/dropbox/lib.php b/repository/dropbox/lib.php
index 002cc74a903..b08ea173e04 100644
--- a/repository/dropbox/lib.php
+++ b/repository/dropbox/lib.php
@@ -90,7 +90,7 @@ class repository_dropbox extends repository {
             'oauth_consumer_key'=>$this->dropbox_key,
             'oauth_consumer_secret'=>$this->dropbox_secret,
             'oauth_callback' => $callbackurl->out(false),
-            'api_root' => 'https://www.dropbox.com/1/oauth',
+            'api_root' => 'https://api.dropbox.com/1/oauth',
         );
 
         $this->dropbox = new dropbox($args);