quickbooks are useless when it comes to connecting to bank feeds.  I had similar issues with Natwest - you would think they could get it right for the major banks -but no.

Freeagent from natwest (which they provide for free) works everytime, so its not about clearing cache etc.

I have a barclaycard feed too - and like you - got frustrated at the lack of connection - which stopped working after a refresh of data.   My issue was that i wasnt getting a connection - even though QBO itself said the connection was made.  Then when i deleted the barclaycard feed entirely and tried again, i ran into other issues.  

This worked for me. 

Instead of selecting the icon for the bank you want, use the search bar at the top of the bank feeds.  Then start typing, and you get a different list of banks to choose from. Pick the one most suitable, and try that.  That took me to the banking authentication via a different page and worked for me.

Hopefully helps someone else out too