Thanks for reaching out to the Community. Allow me to chime in and help you with QuickBooks Online (QBO) transactions issue.
Aside from what Fiat Lux - ASIA mentioned above, may I know if you've already connected your bank account to QBO? If so, are you getting any error messages? Any additional information will be much appreciated.
In the meantime, let's sign in to your QBO account using a private browser (incognito). There are times that the browser is already full of frequently accessed page resources (cache and cookies), causing some unusual responses.
Press Ctrl + Shift + N (Google Chrome).
Ctrl + Shift + P (Firefox).
Control + Option + P (Safari).
Once logged in, go back to the Banking menu at the left pane to double-check.
If they're now showing, return to your default browser and perform a clear cache to refresh the system. However, if the issue persists, try using other supported browsers.