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Keep in mind that the sender ID from the user that is sending the email can be overwritten by Email Sende ID settings under Administration–> Settings:
The format of the email is provided with a template named "Report - {Report Name}" (where {Report Name} is the name of the SSRS report), or "Report - Default" if that is not specified.
E-mail templates for the reports can be found under 'Configuration' --> 'Template Management'
Template files are saved in the path where the application files are stored: /Config/Templates/ReportMessages
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