File Download - Access Denied

Good Day all.

I seem to have run into a hitch. Here is the problem

when a registered user purchases an item and pays for it he/she receives the download link for that item via email. When the user downloads from the link it works.

The thing is (anonymous user) after the completion of payment, the download link seems not to work on downloading multiple items and it displays the following error message " Access Denied. You are not authorized to access this page." when you try to access the file.

If checked the permissions for file downloads and is set to allow anonymous users to download.
The link has not expired as well.

I hope that this information is sufficient.

Any assistance will be highly appreciated.