As LMS365 uses Office 365 to send Email Notifications, first of all, when the user does not receive Notifications, please check the Security & Compliance and start Message Trace in order to see if any messages were sent to this user.
- Open Security & Complicance:
- Click Mail Flow, then Message Trace:
- Click Start a trace, set required settings depending on what you would like to see in Message Trace and click Search.
Here is an example of the report for the last 2 days: