diff --git a/core/admin/mailu/configuration.py b/core/admin/mailu/configuration.py
index 982a1eb0..dac913fa 100644
--- a/core/admin/mailu/configuration.py
+++ b/core/admin/mailu/configuration.py
@@ -54,6 +54,7 @@ DEFAULT_CONFIG = {
     # Advanced settings
     'PASSWORD_SCHEME': 'PBKDF2',
     'LOG_LEVEL': 'WARNING',
+    'SESSION_COOKIE_SECURE': True,
     # Host settings
     'HOST_IMAP': 'imap',
     'HOST_LMTP': 'imap:2525',
@@ -125,7 +126,6 @@ class ConfigManager(dict):
         self.config['QUOTA_STORAGE_URL'] = 'redis://{0}/1'.format(self.config['REDIS_ADDRESS'])
         self.config['SESSION_COOKIE_SAMESITE'] = 'Strict'
         self.config['SESSION_COOKIE_HTTPONLY'] = True
-        self.config['SESSION_COOKIE_SECURE'] = self.config['TLS_FLAVOR'] != 'notls'
         # update the app config itself
         app.config = self
 
diff --git a/docs/configuration.rst b/docs/configuration.rst
index 5ff3546a..9123054c 100644
--- a/docs/configuration.rst
+++ b/docs/configuration.rst
@@ -142,6 +142,8 @@ The ``PASSWORD_SCHEME`` is the password encryption scheme. You should use the
 default value, unless you are importing password from a separate system and
 want to keep using the old password encryption scheme.
 
+The ``SESSION_COOKIE_SECURE`` (default: True) setting controls the secure flag on the cookies of the administrative interface. It should only be turned off if you intend to access it over plain HTTP.
+
 The ``LOG_LEVEL`` setting is used by the python start-up scripts as a logging threshold.
 Log messages equal or higher than this priority will be printed.
 Can be one of: CRITICAL, ERROR, WARNING, INFO, DEBUG or NOTSET.