Data-driven Subscription doesnt send out an email but job history shows its successfull

Hi All

Please give me some advice about this Data-driven Subscription runs every hour misses out once or twice a day, but the subscription job history shows it ran sucessfull but it doesnt trigger the e-mail out.

Is there a way to check on subscription logs that SSRS has triggered the report out to the e-mail server.

Is there a way to add add logs for the e-mail part to make sure it has sent out the email ?

Nothing in the E-mail server logs to show this report email was requested / delivered / rejected by it.

So - Kindy advice me how can I proceed my findings on this.

Thanks a lot in advance.