diff --git a/src/Exception/OAuthException.php b/src/Exception/OAuthException.php
index 2560d0eb..dd9ad62d 100644
--- a/src/Exception/OAuthException.php
+++ b/src/Exception/OAuthException.php
@@ -132,6 +132,8 @@ class OAuthException extends \Exception
                         $authScheme = 'Bearer';
                     } elseif (strpos($authHeader, 'Basic') === 0) {
                         $authScheme = 'Basic';
+                    } elseif (strpos($authHeader, 'MAC') === 0) {
+                        $authScheme = 'MAC';
                     }
                 }
             }