Let's check why you're unable to connect your financial institution to QuickBooks Online, info-loveyourflo.
It's been reported that some customers are getting an error 350/590 when connecting Barclays Bank. And, our Product Team is currently looking into this issue.
If you're receiving the same error, I recommend contacting our QuickBooks Online Team. They can add your account to the investigation (INV-51171) and send you updates via email once resolve.
Here's how to get in touch with them:
Then, you can download transactions from your bank and manually upload them to QuickBooks.
If you aren't getting an error, you can disconnect Barclays Bank on your Banking page. Then, check with your bank for any update and reconnect it to QuickBooks.
Check out this article for additional information: Upgrade your bank feed connection to Open Banking.
Stay in touch with me on how everything turns about the connection. I'll be around until you're able to connect Barclays Bank.