diff --git a/roles/mail/files/sender_blacklist b/roles/mail/files/sender_blacklist
index ab0f2f8..351d2de 100644
--- a/roles/mail/files/sender_blacklist
+++ b/roles/mail/files/sender_blacklist
@@ -8,5 +8,6 @@ cleverep.com       REJECT
 .ru                REJECT
 allsip.ru          REJECT
 clickup.com        REJECT
+secureserver.net   REJECT
 sina.buffy@avantgarde-experts.de OK
 .avantgarde-experts.de OK