I'm happy to help you get back to approving all of your 2019 transactions, but first, there are a few questions I need you to clarify.
Are you manually uploading transactions into QuickBooks?
Where is the December 1st limit showing up?
If the transactions are in QuickBooks, are you approving them under the banking tab?
After you answer these questions, I can help determine where the issue lies. In the meantime, if you're bringing transactions into QuickBooks, Excel files have a limit of 1000 lines. I suggest dividing the transactions into separate files with the line numbers stopping before they hit the limit. This will ensure that all of your bank transactions are coming into the program correctly. You may find this article helpful when importing bank transactions.