When setting up the account with Notezilla , the exact steps of activation was not followed. So you are facing this issue.
Please email (support@conceptworld.com) the following details to us so that we can guide you.
1. Have you already synced your notes from another device with the same sync account or this is the first time you are syncing your sticky notes with the acccount?
2. Which email address has been used to create sync account?