Thanks for posting here, Gerald. I'll provide information about the bank error 509 so you can download and manage your transactions seamlessly.
Before anything else, may I know the name of the bank? Knowing this would greatly assist us in identifying the issue and providing a tailored solution.
Typically, the bank connection error 509 likely arises when you're in the process of connecting your bank account to your QuickBooks Self-Employed (QBSE) account. This error message means your bank needs additional setup to give 3rd party (QuickBooks) access to your account.
Alternatively, your financial institution may be experiencing maintenance issues or security requirements. Therefore, it would be worthwhile to contact your bank to verify if such measures are in place.
I'll also add these articles for reference on categorizing the transactions you download from your bank and for more information about importing transactions:
Keeping your financial records accurate is our utmost priority. Please comment below if you have further concerns about bank errors in QBSE. We're always here to help you out