Failure sending mail: The specified string is not in the form required for an e-mail address.Mail will not be resent.

Hi,

I am getting "Failure sending mail: The specified string is not in the form required for an e-mail address.Mail will not be "resent.

Its SSRS 2012 . SMTP server is Lotus notes server .

I can successfully set the subscription if I enter the email address manually.

<SendEmailToUserAlias>False</SendEmailToUserAlias>

 I have edited the rsreportserver config file with the following . when user click subscripe the To field is populated with login-name .

<SendEmailToUserAlias>True</SendEmailToUserAlias>
      <DefaultHostName>SMTP mail server </DefaultHostName>
      <PermittedHosts>domain name      </PermittedHosts>