I downloaded an e-book yesterday and began reading it. Today, I tried to resume reading it but received an Error message that the book was not downloaded to my computer. I tried re-downloading it but my Library account shows it already downloaded to my di

I downloaded an e-book yesterday and began reading it. Today, I tried to resume reading it but received an Error message that the book was not downloaded to my computer. I tried re-downloading it but my Library account shows it already downloaded to my digital e-reader. How can I fix this?