diff --git a/smtp/msa.go b/smtp/msa.go
index 90d4261..feb6158 100644
--- a/smtp/msa.go
+++ b/smtp/msa.go
@@ -49,7 +49,6 @@ func Start(domain, port, loglevel string, maxSize int, client Client) error {
 	s.ReadTimeout = 10 * time.Second
 	s.WriteTimeout = 10 * time.Second
 	s.MaxMessageBytes = maxSize * 1024 * 1024
-	s.AllowInsecureAuth = true
 	if log.GetLevel() == "DEBUG" || log.GetLevel() == "TRACE" {
 		s.Debug = os.Stdout
 	}