Hi Aditi,
Hope you are doing good.
The datasource file that you are using should have this mapping configured.
Open Configtool->switch to the configuration editor ->mode->configuration->cluster_data->server-> persistent -> com.sap.security.core.ume.service and download the datasource file hat is being used and check if the email details are mapped.
Thank you!
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Kind Regards,
Hemanth
SAP AGS