Hello there, Adavis-asea.

You'll encounter that message if you upload a file with an incorrect format. These are the file formats QuickBooks Online supports:

• Comma-Separated Values (CSV) files 
• Quicken (QFX)
• QuickBooks Online (QBO)
• Microsoft Money (OFX)

Let's make sure you're using the correct format so you can import bank transactions successfully. For more information, check this article: How to upload more than 90 days of bank transactions.

Don't hesitate to visit us if you have other questions.