Allow me to provide some insights on why you're unable to reconnect your bank account to QuickBooks Online.
Being unable to reconnect your bank account in the system can be caused by the new banking regulation. It means that March 14, 2020, bank data can only be downloaded into QuickBooks through Open Banking. This allows customers to share their financial information electronically.
For those financial institutions that do not support this feature, are advised to manually import their bank transactions using CSV file uploads until the new connection is made available.
However, if this option is already available on your bank, I recommend upgrading the bank feed connection so you can now reconnect your accounts.
Please know that our system is updating the bank feeds to comply with new Open Banking regulations.
You can check out these articles below to learn more about this process, and see what are those financial institutions that currently supports this feature: