The notification service is supplied by Google service, so if you can get notification before, and suddenly can not receive it, please check all kinds of access.
Steps to check
1. Enable and disable your notification option again in meross app. Try to open and close the door again to test.
2. If the auto close or overnight/overtime notification is not working, remove original setting, and set it again to try.
3. If you upgrade your phone OS version, or reinstall meross, please check if you grant meross app notification access in OS system. For example, iOS is Settings->Notifications->meross->Allow Notifications.
4. Remove the device and pair it again. Better uninstall the meross app and install it again.
If above points do not help, please email your meross account to firstname.lastname@example.org, we will help solve the issue timely.