Hi there, @w-evans-electric2.
There may have been ongoing changes and improvements in the security and connection between your bank and QuickBooks Self-Employed (QBSE). To check this, you can log in to your online banking to verify if they are preparing for system maintenance.
Also, I want to ensure that we get aligned with the troubleshooting steps that I can share. May I know the financial institution that you're trying to reconnect with QuickBooks? This way, I can check if there's an open investigation between syncing your bank to QuickBooks.
For now, if you want to categorise your latest transactions, I suggest manually importing the transactions to QBSE. You may need to review the Transactions menu and categorise the transaction before importing the banking entries manually. This way, you can identify the entries easier when putting it to the right SA103F Categories.
Feel free to add the details here and if you have other concerns. I'll keep my eyes on this post. Keep safe, w-evans-electric!