Hi there, elenamanfredi-he.
I appreciate letting me know about the issue you're experiencing with Barclays. I'm here to help you get your bank account connected to QuickBooks Online.
First, let's access your account via the Incognito window or private browser. It doesn't store data, which makes it a good place to start to see if there are any issues with the browser.
Here’s how to open a private window:
If you're able to connect your account, let's proceed by clearing your browser's cache. Doing so will remove the unnecessary files stored in your browser. You can also use other compatible browsers as an alternative.
In the meantime, you can bring transactions into QBO using the WebConnect feature.
You can check out this link about matching bank transactions for reference: Match and categorise bank transactions in QuickBooks Online.
I'll be right here if you need more help with banking concerns in QBO.