diff --git a/app/services/email_service.py b/app/services/email_service.py
index f6af59a..7b1fb0d 100644
--- a/app/services/email_service.py
+++ b/app/services/email_service.py
@@ -17,11 +17,15 @@ OUTLOOK_CONTENT_ID_PROP = "http://schemas.microsoft.com/mapi/proptag/0x3712001F"
 def _build_mime_message(to_address, subject, html_body, sender_name, attachments):
     """Собирает MIME-сообщение с inline-вложениями."""
     config = current_app.config
-    sender = config.get("MAIL_DEFAULT_SENDER") or config.get("MAIL_USERNAME", "")
+    sender_address = config.get("MAIL_USERNAME", "")
+    if not sender_address:
+        raise ValueError("MAIL_USERNAME должен быть указан в конфигурации")
+    # Имя отправителя — отдельно от email-адреса
+    display_name = sender_name or config.get("MAIL_DEFAULT_SENDER") or ""
 
     msg = MIMEMultipart("related")
     msg["Subject"] = subject
-    msg["From"] = formataddr((sender_name, sender))
+    msg["From"] = formataddr((display_name, sender_address))
     msg["To"] = to_address
     msg["Date"] = formatdate(localtime=True)
     msg.attach(MIMEText(html_body, "html", "utf-8"))