diff --git a/lib/bing-ads-reporting/service_core.rb b/lib/bing-ads-reporting/service_core.rb
index 26d6576..c0cf9e0 100644
--- a/lib/bing-ads-reporting/service_core.rb
+++ b/lib/bing-ads-reporting/service_core.rb
@@ -1,6 +1,6 @@
 module BingAdsReporting
-  class AuthenticationTokenExpired < Exception; end
-  class AuthenticationViaOAuthIsRequired < Exception; end
+  class AuthenticationTokenExpired < StandardError; end
+  class AuthenticationViaOAuthIsRequired < StandardError; end
 
   class ServiceCore