fix(smtp): force enabling SSL does not work (#2777)

pkg/email/smtp.go

@@ -121,17 +121,17 @@ func (client *SMTPPool) Init() {
 			}
 		}()
 
-		tlsPolicy := mail.TLSOpportunistic
-		if client.config.ForceEncryption {
-			tlsPolicy = mail.TLSMandatory
-		}
-
-		d, diaErr := mail.NewClient(client.config.Host,
+		opts := []mail.Option{
 			mail.WithPort(client.config.Port),
 			mail.WithTimeout(time.Duration(client.config.Keepalive+5) * time.Second),
-			mail.WithSMTPAuth(mail.SMTPAuthAutoDiscover), mail.WithTLSPortPolicy(tlsPolicy),
+			mail.WithSMTPAuth(mail.SMTPAuthAutoDiscover), mail.WithTLSPortPolicy(mail.TLSOpportunistic),
 			mail.WithUsername(client.config.User), mail.WithPassword(client.config.Password),
-		)
+		}
+		if client.config.ForceEncryption {
+			opts = append(opts, mail.WithSSL())
+		}
+
+		d, diaErr := mail.NewClient(client.config.Host, opts...)
 		if diaErr != nil {
 			client.l.Panic("Failed to create SMTP client: %s", diaErr)
 			return

service/admin/tools.go

@@ -139,15 +139,16 @@ func (s *TestSMTPService) Test(c *gin.Context) error {
 		return serializer.NewError(serializer.CodeParamErr, "Invalid SMTP port", err)
 	}
 
-	tlsPolicy := mail.TLSOpportunistic
-	if setting.IsTrueValue(s.Settings["smtpEncryption"]) {
-		tlsPolicy = mail.TLSMandatory
-	}
-	d, diaErr := mail.NewClient(s.Settings["smtpHost"],
+	opts := []mail.Option{
 		mail.WithPort(port),
-		mail.WithSMTPAuth(mail.SMTPAuthAutoDiscover), mail.WithTLSPortPolicy(tlsPolicy),
+		mail.WithSMTPAuth(mail.SMTPAuthAutoDiscover), mail.WithTLSPortPolicy(mail.TLSOpportunistic),
 		mail.WithUsername(s.Settings["smtpUser"]), mail.WithPassword(s.Settings["smtpPass"]),
-	)
+	}
+	if setting.IsTrueValue(s.Settings["smtpEncryption"]) {
+		opts = append(opts, mail.WithSSL())
+	}
+
+	d, diaErr := mail.NewClient(s.Settings["smtpHost"], opts...)
 	if diaErr != nil {
 		return serializer.NewError(serializer.CodeInternalSetting, "Failed to create SMTP client: "+diaErr.Error(), diaErr)
 	}