You can only connect your business to one Square account, so be sure that you've decided upon which Square account you want your business' Square payments to go to. If you have multiple Staff and each have their own Square account, funds will not route to their respective accounts.
Note: If you have multiple businesses set up under your Square account, you will not be able to choose which account you want to process the credit card payment during checkout. The Square account that is connected to MassageBook will be the account that processes the charge.