What if I can't redeem my ebook voucher?

Make sure you are using the correct voucher and not a previously redeemed book voucher. For CompTIA, you must enter the access key first at this site:  https://learn.comptia.org/access-key. After entering the voucher key, you can proceed to create a new account or login. Make sure you use your personal email and not the divergence.one username, as it is not an email address.