Hi there trucold.hr,
It's vital that all your transactions are correctly entered in your books so your account balances can be accurate. QuickBooks Online is a great tool able to import transactions from your bank account in order to save you time with data entry. I can provide some information about banking.
If you're missing some transactions for a previous period, but your newest transactions are importing properly, you can import the transactions of the missing periods using one of the file extensions mentioned in this article about how to manually upload transactions into QuickBooks Online. There are also steps listed in the guide in order to know how to import these transactions.
If you currently have an error preventing you from importing the newest transactions, I recommend clicking on the Pencil Icon located to the right of the affected account in the Banking tab to update the sign-in info. Enter the information as if you were to log into your bank's website to update the connection information. If that doesn't import the missing transactions or fix the connection issue, I recommend reaching out to the QuickBooks online support team. They'll be able to verify your QuickBooks account in a secure setting in order to be able to provide more troubleshooting steps as well as notify our engineers if necessary. You can reach out to them using one of these methods:
Schedule a Callback or start a Chat: click (?)Help in the upper right > type and enter "Contact support" into the QB Assistant > click Contact Us > explain your situation > click Let's Talk > choose Get a callback or Start a Chat.
Social Media: Facebook or Twitter,
If you have any other questions, feel free to reach out here.
