This error message is triggered when:

1. The connection is no longer valid between both platforms. Please check here how to resolve the issue.
2. Not all required fields have been filled out. The following fields are required: 
   1. merchant 
   2. amount
   3. currency
   4. date
3. Expenses have been paid with 'cash' or a 'personal credit card' but have not been marked as reimbursable. 

4. There are expenses that fall outside of the accounting period in Quickbooks. Please check here how to resolve the issue. 
   
   

   Note: In order to check which expense is blocking the export, it is advised to export in smaller batches. You can limit the number of expenses being exported by selecting the accounting end date. 

To see which expense will get exported first, click on the 'date' column in your expense overview: