Did you encounter any specific error while trying to link your account? When connecting an account in QuickBooks, you'll see several options for Barclays Bank.
To ensure you're linking the correct finance company, as an initial step, let's log in to the bank's website. Once signed in, copy its URL. Then, paste it in the Connect an account window's search box. This will let you log in to your correct bank.
Here's how:
Go to the Banking menu.
Select the Add account button.
Past your bank's URL in the Connect an account search box (example: http://www.chase.com).
Enter your User ID or Email and Password.
Click Continue.
Follow the steps to successfully connect your bank.
After that, QuickBooks will automatically download your most recent transactions. To help you manage and categorise your bank transactions, see these articles for your reference: