To build the base of the cash flow, Float needs to sync at least one bank account from QuickBooks. If no bank accounts are synced the base of the cash flow can't be built and the 'no bank accounts' error will be displayed.
If you haven't yet connected a bank account to QuickBooks you will need to do that, along with creating at least one transaction, before the cash flow can be created in Float.
Once a bank account is connected you can resync Float and that bank account will be introduced into the cash flow.
If you have already connected bank accounts in QuickBooks and are seeing the 'no bank accounts' error please get in touch with firstname.lastname@example.org.