diff --git a/blacklist_sender_domain.map b/blacklist_sender_domain.map
index 4baea52..2d70393 100644
--- a/blacklist_sender_domain.map
+++ b/blacklist_sender_domain.map
@@ -7,3 +7,4 @@ b2bmailsolutions.com
 sys.ba
 callloop.com
 tholen-gruppe.de
+smtpcheck.co