Let's sort this out so we can fix this sync issue with your bank transactions.
There are possible reasons why you're missing your bank transactions in QuickBooks Online (QBO). Among these are the following:
Some banks and credit card companies don't post transactions for download until later in the day or the next morning.
Depending on which bank it will show a transaction on their website but won't download the transaction until it posts.
If the missing transactions are the most recent ones, wait at least 24 hours in case your bank doesn't make them available immediately.
If you're using different bank to different QuickBooks account, you'll have to take note of the above mentioned.
If you're using the same bank account to both of your QuickBooks account, then you can update the other account where there are missing transactions. This will help refresh the connection between your bank and QuickBooks for updates to sync.
Here's how:
Go to the Banking menu,
Select Update. If you only want to update some accounts, select the unwanted ones, then select Updatenow.
If asked, enter your Multi-Factor Authentication (MFA) credentials. Then select Continueupdate.
Utilize the trial version of MT Online to isolate the issue. It is designed to import into any bank or credit card in QuickBooks Online, so there is no specific setting needed. If the same error persists, there is an ongoing problem at your bank or connection.