If a message pops-up stating that this account has already been activated by another used, you might have previously activated an alternate email login on the OfficeMax eBooks  application on your device.
 

To rectify the problem:

1. Click on the Gear Icon on the bottom left hand side of the page and click Deactivate.
    
2. Sign Out of this account and Log Back In to eBooks reader using the correct login details.
    
3. Click back on the Gear Icon and select Activate while logged in with the correct details.
    

If you are continuing to have problems, drop by 1 Degree!