Bell notification menu is not displaying any notification / approval, But exist in BPM Worklist

Summary

Notification is only shown in the worklist, recently we are not able to get notifications in the bell notification menu for almost many users. Some of the notification which is not shown in the bell notification menus are Goal Plan Notification (FYI), Employment, Performance (FYI), Saved Transaction, Document Record ... etc

Note that previously it is working fine.

Content (required):

Notification is only shown in the worklist, recently we are not able to get notifications in the bell notification menu for almost many users. Some of the notification which is not shown in the bell notification menus are Goal Plan Notification (FYI), Employment, Performance (FYI), Saved Transaction, Document Record ... etc