If you log into to an iCertifi app and it wont unlock on another device on your account. Here is a quick fix.
- Select the subscribe tab > log out
- Log in > create new account. Use a different email address for the new account, you can re use your old password if you like.
- Log in to the relevant iCertifi app with your new email and password details and it should unlock instantly.
The account/log in feature simply tells your devices on your iTunes account you are a subscribed user. Your subscription will not be affected
Remember each iCertifi app must be purchased separately.