diff --git a/smtp/server.go b/smtp/server.go
index dfab3db..62b9cdb 100644
--- a/smtp/server.go
+++ b/smtp/server.go
@@ -6,6 +6,7 @@ import (
 	"os"
 	"time"
 
+	"github.com/emersion/go-sasl"
 	"github.com/emersion/go-smtp"
 	"gitlab.com/etke.cc/go/logger"
 )
@@ -57,6 +58,19 @@ func NewServer(cfg *Config) *Server {
 	if log.GetLevel() == "DEBUG" || log.GetLevel() == "TRACE" {
 		s.Debug = os.Stdout
 	}
+	// LOGIN auth method, ref: https://github.com/emersion/go-smtp/issues/41#issuecomment-493601465
+	s.EnableAuth(sasl.Login, func(conn *smtp.Conn) sasl.Server {
+		return sasl.NewLoginServer(func(username, password string) error {
+			state := conn.State()
+			session, err := receiver.Login(&state, username, password)
+			if err != nil {
+				return err
+			}
+
+			conn.SetSession(session)
+			return nil
+		})
+	})
 
 	server := &Server{
 		msa:     s,