Transfer Domain Between Squarespace Accounts

How can I transfer a domain between my two (2) Squarespace accounts?

I already requested from the Squarespace account I want to transfer OUT the domain authorization code.  A few hours later, I received the authorization code in my email.  And I logged off all squarespace accounts, then I logged into the squarespace account I intend to transfer IN the domain.  I clicked on the "Transfer" button in the Domain section, and then squarespace prompts me for the website.  However, as soon as I enter the website and hit the little arrow to move forward, I get a red message that states "XYZDomain.org is already managed by Squarespace."  Thus, I am unable to move forward to provide the authorization code.  

Domain moves between Squarespace sites do not use transfer. Here is the guide to move a Squarespace domain between Squarespace sites: 

Move a Squarespace domain to another Squarespace website.