Thanks for joining in on this thread, Sewing RL.

I'll share some information about the error and steps to help you fix it.

We currently don't have any reported issues regarding the bank error 103. However, you'll encounter this due to the following:

• An incorrect user ID or password for the bank account you’re trying to connect. 
• Your bank needs permission to connect your account to another service, including QuickBooks Online.

Since your credentials are correct, you'll want to visit your bank’s website. Then, check if your bank has this requirement. If so, follow your bank’s instructions to turn it on.

Once done, sign in to your bank account in QuickBooks by following these steps:

1. Go to Transactions or Banking on the left panel.
2. From the Banking tab, select the bank or credit card account you need to update.
3. Select Edit and click Edit sign-in info. If your web browser auto-fills the user ID and password fields, clear them. This ensures your browser doesn’t put in old info by mistake.
4. Manually type in the user ID and password for your bank account. If your bank offers a Show option, select it so you can confirm you entered the password correctly.
5. Hit Update.

You can click on this article for reference: Fix bank error 103.

In case you have all the transactions updated in the For review tab, you can start categorizing and matching them. The steps are included in this link: Categorize and match online bank transactions in QuickBooks Online.

If you're still getting the same result, I recommend reaching out to our Customer Care Team. They can review your account and investigate what's causing this error. 

Please take note that our support for QuickBooks Online Payroll Core and Premium is available from M-F 6 AM to 6 PM PT. For QuickBooks Full Service Payroll, QuickBooks Online Payroll Elite/Premium, we're available any time, any day.

Here are the steps:

1. Click the Help icon located in the upper right-hand corner.
2. In the Search window, click the Contact Us button located at the bottom.
3. Enter your question and click Let's talk.
4. Choose either Chat with us or Have us call you.

If you have the new QuickBooks Assistant help update, you can follow these steps:

1. In your QuickBooks Online account, go to the Help > Assistant.
2. Type Talk to a human and enter what do you need help with.
3. Click No if none of the articles shared are helpful and select Chat with us or Have us call you.

You can also get our direct phone number in this article: Contact Payroll Support.

You're always welcome to post a reply here if there's anything else you need. Have a good day ahead.