Using licence on 2 computers

[kiddts15]

My parents installed using the license code on their laptop and completed their taxes. I have now tried to install it on my MAC and when entering the license code I keep getting the following error "Something's not right, try re-entering your code." I have retried and verified that I am entering it correctly. WE have not used the maximum number of returns allowed.

My question is, do I have to log in under the account my mother created to completed on my MAC as  I created my own account and am trying to entire the code under that. 

The FAQ's say you can enter on more than one device.

[TurboTaxSusan]

If you have TurboTax Online, you can only use the code once in one account. Using the code again will give an error message. You will need to login to the account where the code was first entered to prepare your return.