This is not the kind of experience that we want you to have while using QuickBooks Online (QBO), @Antoinette12.
Let's resolve the error you're having to get your latest transactions.
Can you tell me more about the bank with which you're having issues? That will surely help me in providing an exact answer to your problem.
Usually, QuickBooks downloads the latest available transactions every night around 10:00 PM (PST). In case you're having bank errors, you'll need to resolve them first, so you'll get your latest transactions.
Check out this article for more information about the bank error you're having and on how to resolve it: What to do if you get a bank error or can't download transactions in QuickBooks Online.
Missing transactions in the account can be added manually in QBO through the WebConnect process. You’ll have to manually download the transactions from the bank. Then, upload the file to your account.
Check this article for more information about adding your bank transactions in QBO: Manually upload transactions into QuickBooks Online. It'll guide you on how to download and upload the file to your QuickBooks account.
About logging in to the account, we send you a one-time confirmation code through your email or mobile device. Works as second layer protection of your account. If you're having trouble logging in, you can clear your browser's cache to resolve it.
Refer to this article for more information about different solutions that you can try and on how to clear your cache and cookies: Fix common sign-in errors in QuickBooks Online.
Once you get your missing transaction, you can now match and categorize. Then, reconcile it to ensure your books are accurate and there aren't any duplicate transactions:
That should do it! If you need further help finding your transactions or resolving bank errors, let me know in the Reply section below. Have a great rest of the day!
