Let's check if you're using a Cash or Accrual basis. The difference between these two is how the date is determined for reporting. Also, make sure that you've chosen the correct Report period.
If the result is still the same, try signing into QuickBooks Online (QBO) using a private browser (incognito). This will help us check if the browser is already full of frequently accessed page resources, causing some unusual responses.
Here's how:
Press Ctrl + Shift + N (Google Chrome).
Ctrl + Shift + P (Firefox).
Control + Option + P (Safari).
Once logged in, run the report again to double-check. If everything looks good, return to your default browser and perform a clear cache to refresh the system. However, if the issue persists, try using other supported browsers.