diff --git a/config.py b/config.py
index a54a11f1..dd23da0b 100644
--- a/config.py
+++ b/config.py
@@ -70,7 +70,6 @@ class Config:
     NOPAQUE_ADMIN = os.environ.get('NOPAQUE_ADMIN')
     NOPAQUE_DATA_DIR = Path(os.environ.get('NOPAQUE_DATA_PATH', '/mnt/nopaque'))
     NOPAQUE_IS_PRIMARY_INSTANCE = os.environ.get('NOPAQUE_IS_PRIMARY_INSTANCE', 'true').lower() == 'true'
-    NOPAQUE_MAIL_SUBJECT_PREFIX = '[nopaque]'
     NOPAQUE_SERVICE_DESK = 'gitlab-ub-incoming+sfb1288inf-nopaque-1324-issue-@jura.uni-bielefeld.de'  # noqa
     NOPAQUE_SOCKETIO_MESSAGE_QUEUE_URI = os.environ.get('NOPAQUE_SOCKETIO_MESSAGE_QUEUE_URI')