Im stuck in a cycle of reconnecting my credit card feed. Success > reconnect etc How to i resolve this?

Thanks for reaching out to the Community, @dafydd-henry.

May I know what specific error you're getting? I'd appreciate it if you can provide more info about this so I can give you an accurate resolution to resolve the issue. 

In the meantime, log in to your QuickBooks Online (QBO) company using a private browser. This prevents storing cache and cookies that might cause problems when running websites. 

Below are the shortcut keys you can use:

• Google Chrome: click Ctrl + Shift + N 
• Mozilla Firefox and Microsoft Edge: press Ctrl + Shift + P
• Safari: hit Command + Shift + N

Once signed in, reconnect your credit card account again. 

If this works, return to your regular browser and clear the cache. This will remove the stored cache or cookies to refresh your browser's background process. If the same thing happens, use another supported browser. It could be that the one you're currently using has a temporary issue with QuickBooks. 

Once connected, you have to log out and log in to your account and check the Transactions/Banking menu. 

Then, to review each downloaded transactions, you have to categorize and match them into QuickBooks Online.

Keep me posted if you have any other concerns about connecting your credit card to QuickBooks. I'm always here to help. Have a great day ahead.