diff --git a/src/oauth2server/Server.php b/src/oauth2server/Server.php
index 5c5e7125..3819e713 100644
--- a/src/oauth2server/Server.php
+++ b/src/oauth2server/Server.php
@@ -2,6 +2,12 @@
 
 namespace LNCD\OAuth2server;
 
+class OAuthSererClientException extends Exception {}
+
+class OAuthServerUserException extends Exception {}
+
+class OAuthServerException extends Exception {}
+
 class Server
 {