You will want to check email errors from your email service in ACP -> System -> Email Settings.
If there are no errors, we would require access to provide further assistance:
We would need to look further into this for you, however the access details on file appear to be incorrect or missing. Could you please update these details by visiting your client area, selecting the relevant purchase, then clicking "Review/Update Access Information" under the "Stored Access Information" section.
We look forward to further assisting you.