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.
Select Contact Us to connect with a live support agent.
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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.