Hi there, MR88.
The guideline for Online Banking has always been the same when connecting parent and sub-accounts. It might have initially allowed you to connect both, but was eventually detected by the system. This can be the reason why you're now getting the error when connecting the fourth sub-account.
You can read more details about this in the Connect the accounts to Online Banking section of this article: About Bank or Credit Card Subaccount Setup.
Feel free to refer to these articles for additional guidance and reference when using Online Banking:
Reach out to us again any time of the day if you have other questions or concerns when working in QBO. We'd be happy to help you again.
