My bank connection isn't work again

It's nice to have you in the Community, @danontheblink.

I've got some steps we can perform to see if this is just triggered by your bank, or in QuickBooks Self-Employed (QBSE).

Let's try clicking on Refresh All multiple times on your Banking page to refresh the connection between your financial institutions and QBSE. Then, try connecting your bank account again. If the same thing happens, just manually import your bank transactions using .CSV file. You can get this file from your bank's website. Let me show you how:

1. Got to the Gear icon.
2. Select Imports.
3. Tap Import older transactions and follow the on-screen instructions.
4. Tick Import.

May I also know the name of your bank? This way we can better isolate if there's an issue with it. There are a few reasons why you're getting banking errors in your account. Among these are:

• The bank recently made some changes with their security feature or connection.
• Log-in credentials set up in QBSE don't match with the online banking login.
• QBSE is unable to connect to your bank's website.

For more details about this one, see this article to know how to add older transactions in QBSE: Add older transactions to QuickBooks Self-Employed. Then, categorise and edit your transactions after. Once done, please contact our QBSE Customer Support Team. They'll pull up your account in a secure environment and investigate what's causing this banking error. 

Feel free to visit our Banking page for more insights about managing your bank transactions.

If you have any other questions related to QuickBooks Self Employed, feel free to leave a comment below. I'll be happy to help you further. Take care and have a great day!