We currently have an on-going issue where QuickBooks Online users can't export reports to Excel. Rest assured that our product engineers are diligently working on a fix.
But I've got a workaround for you. Let's save a customized version of your Journal Entry (JE) Detail report, then export it from there.
Here's how: 1. Click the Save button. 2. Go back to Reports menu. 3. Select the Custom Reports tab. 4. Under the ACTION column, select Export As Excel from the drop-down list.
Also, I recommend contacting our QuickBooks Customer Care so they can add your account to the list of affected users. This way, you'll receive an email regarding the issue once updates become available.
Don't hesitate to leave a comment below if you have additional questions. Have a great day!