I have been connected to my bank successfully for weeks. This week I cannot download any new transactions. No error is displaying. Authentication seems to work.

Hi there, sophie6.

Thank you for posting here in the QuickBooks Community.

 I suggest doing a manual update to sync your transactions in QBO.

Here's how:

1. At the left panel, select Banking.
2. Select Update.

If the given steps above will not work, I recommend to  Sign in to your bank’s website to check. First, get the URL from QuickBooks:

1. Select the Banking menu at the left panel.
2. Select Add account( you just need the listed URL)
3. Search for your bank and select it.
4. Copy the URL listed on the page.
5. Sign in using your bank username and password and make sure you're using the one in QuickBooks.

If you already sign in to your bank's website:

1. Check your account page for messages, notifications or alerts.
2. Check your bank’s website about new security requirements.
3. If everything is good, go back to the Banking menu in QuickBooks.
4. For the bank account, select the blue tile.
5. Click Update.

You can check out to this article for more information and help you to fix specific download errors: What to do if bank transactions won’t download.

You can check out this article to help match and add your transactions: Add and match downloaded bank transactions [Video].

Please know that you're always welcome to post if you have any other concerns. Wishing you and your business continued success.