I've got troubleshooting steps to help you connect your ING Bank to QuickBooks, admin368.

First, please let us know if you encounter any specific error messages when connecting to your bank. Any information will help us provide the most accurate solution.

In the meantime, please check your financial institution's website for any notifications or alerts about ongoing maintenance that may prevent you from linking your bank.

Once you have verified everything on your bank's end and the issue persists, clearing your browser's cache will help the program run smoothly and eliminate technical issues. You can also try using other devices and supported browsers as alternatives.

For your future reference you can check out this article to learn how to match your bank transactions and categorize them afterward in QBO: Find, categorise, and edit transactions in QuickBooks Online.

The Community is always here to help if you have other questions or concerns.