See explanation below.
Explanation:
You need to add a write-off reason for USMF and set it as the default.
* Go to Navigation pane > Modules > Credit and collections > Setup > Accounts receivable parameters.
* Click the Collections tab.
* Click the Edit icon in the Write-Off section.
* Add a new Write-Off reason if it doesn't exist.
* Tick the "Default" checkbox next to the new Write-Off reason.
* Click the Save button to save the changes.