diff --git a/app/imap_connect.py b/app/imap_connect.py
index e2daf98..aadc9f1 100644
--- a/app/imap_connect.py
+++ b/app/imap_connect.py
@@ -27,7 +27,7 @@ def run():
             if not IS_DEV: 
                 return
         else:
-           _server.set_flags(uid, ['\\SEEN','Processed_{}'.format(parser_id)])
+           _server.add_flags(uid, ['\\SEEN','Processed_{}'.format(parser_id)])
         logging.info("got Mail {} von {}".format(email_message.get('Subject'), email_from))
         if any(mail in filter_from for mail in email_from):
             # Get HTML body