I want to make sure you can connect your Starling Bank account, amazon-mootech-c.
If it's a new connection, I recommend validating the credentials first on the financial institution’s website. Once verified, try connecting your bank account again to your QuickBooks Online account.You can follow the detailed steps outlined in this article: How to connect your bank account & credit cards.
Once your bank account is connected and downloads transaction, you can now review and categorise your transactions.
Keep me posted if you have any other banking concerns. I'm always here to help.