Hello, MR88. 

Thank you for getting back to us. As mention by my colleague above, initially they will allow you to connect both a parent account and its subaccounts. However, if you try to attach both, and the system detects it, you’ll get a message that the account is already connected. 

You may consider contacting our customer support team to help you further with this. 

On the other hand, If you need further help reconciling your account, see how to reconcile accounts for a step-by-step guide.   

Drop me a comment below if you have any other questions. I'll be more than happy to help. Wishing you a good one. Stay safe!