Let's resolve the error you're having to connect your bank successfully, @TM31313.

Can you tell me more about the bank that you're having trouble with and the error you're having? That'll help us get the best resolution for the error you're having.

The error can be caused by any of the following:

• There is an issue with your bank.
• Your Internet connection isn't working properly.
• One or more bank accounts in your company file have a problem.
• Your bank's file isn't compatible with QuickBooks.
• You're using a version of Internet Explorer that is no longer supported.
• You're using an out-of-date QuickBooks version.

Before you begin troubleshooting, review the following guidelines:

• Make sure to create a backup of your company file, so if you ever have an issue, you can recover your data from your backup.
• Access your bank's website from outside of QuickBooks and that there are no pending alerts.
• You can connect to the Internet and your Windows firewall isn't interfering with your QuickBooks connection.
• You're using a version of QuickBooks that is supported. If not, download and install the most recent version of QuickBooks.
• Install the most recent version of Internet Explorer.

You can now proceed to the following steps:

1. Check your Internet security requirements to secure your data when connecting to your bank, Internet Explorer and QuickBooks uses the TLS 1.2 security protocol.
2. Download bank feed transactions in a test company file.
3. Check if the file from your bank is compatible with QuickBooks.
4. Refresh the connection with your bank.
5. Create and merge accounts.
6. Turn off and set up online banking for other accounts.

For detailed guidance in resolving the error you have, check out this article: Fix OL and OLSU Bank Feeds errors in QuickBooks Desktop.

Once you get your latest transactions, you can now review and match transactions: Add and match Bank Feed transactions in QuickBooks Desktop. That will also guide you on how to create rules to categorize transactions. 

Let me know if you need further help in resolving the bank error. I'm always glad to help in any way I can. Have a great rest of the day!