Thank you for posting here in the Community, @spspadyana-gmail. I appreciate you for pointing out this error message.

I checked and found an open investigation for this specific error message. I suggest you contact our Technical Support team for further assistance. They can add you to the list of our affected users, and you'll get a notification email whenever an update becomes available. 

See this article for the steps: QuickBooks Online Support. It includes their hours of operation, so you know when they're available. 

Post a reply if you have other questions about importing files in QBO. I'll get back to you as soon as I can. Enjoy the rest of the day!