Ensure the configurations are selected correctly by navigating to:
Setup → Apps and Add-ons → Integrations → Azure AD User Sync.

Also, verify that the user has been synced at least once previously through Azure AD User Sync or Import from Azure.
This can be checked in the Sync Report or in the System Log.

a. If sync reports are available

1.  Search for the user’s Object ID or Email ID in all the sync reports.
   (At least one match should be found for Add or Update.)
2. Find the user delete entry in the sync report and check the delete configuration printed before that.
   (In the listed logs, look for the log entry right before the deleted date and verify the chosen options for the configurations:
   "When users are deleted in Azure AD, select the following action in ServiceDesk Plus" and
   "When users are moved to trash in Azure AD, select the following action in ServiceDesk Plus.")

b. If sync reports are not available or user data is not found in the sync report

1. Search the Email ID in the System Log by setting the filter to This Year or Last Year.
   
2. Get the date from the customer when the user was deleted in Azure.
   (They can find this in the Azure Audit Logs.)
3. Check the configuration for that sync entry from the System Log.
   

c. If the issue is not resolved

1. Affected user's Email ID and Object ID
   (The Object ID can be found in the Azure profile. If the user is deleted, it can be found in the Azure Audit Logs.)
2. Available Sync Reports
   
3. The following System Logs exported as CSV or XLS