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

Question

Users with subscriptions to SSRS reports are not receiving their reports. When I go to Manage > Subscriptions I see several subscriptions with the error Failure sending mail: The specified string is not in the form required for an e-mail address. Mail will not be resent. We migrated from Sharepoint on-prem to the cloud version a few months ago and it's possible this has been an issue since then but only reported today. How do I resolve this issue?

This may have started after we migrated our Sharepoint site from on-prem to the cloud. We are also using O365.

I tried testing with my own login and even tried manually typing in my email address but it still failed. I know there are several posts on the internet related to this issue. I found this link and wanted to see if you could confirm if these are the changes I need to make, https://learn.microsoft.com/en-us/answers/questions/587905/ms-sql-reporting-services-error-34the-specified-st.html.

I compared out settings to these and the first value is set to True and there is nothing populated for the hostname. We do have the SMTPServer populated in the config. We don't want users typing in their email address so I believe we'd want to leave the sendemailtouseralias to True.

Set <SendEmailToUserAlias> to False.

Set <DefaultHostName> to the Domain Name System (DNS) name or IP address of the SMTP server or forwarder.

Answer 1

Hi @Lela Keller ，
User-defined subscriptions that are created according to the permissions granted by the Manage individual subscriptions task contain a pre-set user name that is based on the domain user account. When the user creates the subscription, the recipient name in the To: field is self-addressed using the domain user account of the person creating the subscription.

If you are using an SMTP server or forwarder that uses e-mail accounts that are different from the domain user account, the report delivery will fail when the SMTP server tries to deliver the report to that user.
See more: https://learn.microsoft.com/en-us/sql/reporting-services/install-windows/e-mail-settings-reporting-services-native-mode-configuration-manager?view=sql-server-ver16#configuration-options-for-setting-the-to-field-in-a-message

Best Regards,
Joy

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