diff --git a/flask_mongoengine/sessions.py b/flask_mongoengine/sessions.py
index 756359ee..2a8df49d 100644
--- a/flask_mongoengine/sessions.py
+++ b/flask_mongoengine/sessions.py
@@ -56,7 +56,7 @@ def get_expiration_time(self, app, session) -> timedelta:
         return timedelta(**app.config.get("SESSION_TTL", {"days": 1}))
 
     def open_session(self, app, request):
-        sid = request.cookies.get(app.session_cookie_name)
+        sid = request.cookies.get(app.config["SESSION_COOKIE_NAME"])
         if sid:
             stored_session = self.cls.objects(sid=sid).first()
 
@@ -81,7 +81,7 @@ def save_session(self, app, session, response):
         # If the session is empty, return without setting the cookie.
         if not session:
             if session.modified:
-                response.delete_cookie(app.session_cookie_name, domain=domain)
+                response.delete_cookie(app.config["SESSION_COOKIE_NAME"], domain=domain)
             return
 
         expiration = datetime.utcnow().replace(tzinfo=utc) + self.get_expiration_time(
@@ -92,7 +92,7 @@ def save_session(self, app, session, response):
             self.cls(sid=session.sid, data=session, expiration=expiration).save()
 
         response.set_cookie(
-            app.session_cookie_name,
+            app.config["SESSION_COOKIE_NAME"],
             session.sid,
             expires=expiration,
             httponly=httponly,