I can't connect to Barclays account, i get error 508

Let's perform some troubleshooting steps to connect your Barclays account for online banking, harry1.

I've checked here on our end and there's no reported case about this error message. It's possible QuickBooks Online (QBO) is unable to connect to your bank's website. These errors usually fix themselves by manually updating your bank account. Just go to the Banking page, then tick the Update button and wait for 2 or 3 hours. 

If you're trying to connect via Open Banking, just follow the detailed steps in this article: Connect Your Bank Feed via Open Banking.  Just in case you encounter another error message, check out the Open Banking Connection Errors article to troubleshoot the problem.

If the same thing happens, I'd suggest contacting our Customer Support Team. They'll pull up your account in a secure environment and investigate what's causing this issue. 

You can request a callback from our support agent. This way, you won't have to wait on the line.

Here's how:

1. Click the Help icon on the top right. 
2. Tap the Contact Us button at the bottom. 
3. Enter a short description of your concern. 
4. Tick Continue. 
5. Choose Message an agent to connect with our support. 

In the meantime, import your bank transactions using CSV into QBO.

I've got a link where you can find articles about managing bank feeds: https://quickbooks.intuit.com/learn-support/banking/misc/02/uk-banking?label=QuickBooks%20Online.

Fill me in if you need a hand with reconciling your accounts or any QBO related. I'll be here to ensure your success. Keep safe and healthy.