Symptoms
Order is stuck in "No Payment Method Attached".
Cause
Either customer does not have any default payment method that is applied automatically or there was no such method during order placement.
Resolution
Check whether the customer has payment method in "Active" status and marked as "Auto Payments" at customer's account Payment Methods tab. In case he does select appropriate payment method and click "Mark as Default" button. To process affected orders refer to "Paying Order" documentation article.