Barclays may have updated their security details or having system maintenance. That said, I recommend updating its connection to your QBSE account.
This will refresh the connection between your bank and our software.
Let me show you how:
Click the Gear icon.
Select Bank accounts.
Click Refresh all.
If the issue persists, I strongly suggest reaching out to our Care Support team. They have tools to create a new case and escalate it with our product engineers: