This error appears when the Document Name Column has not been configured in the Output Configuration. AnyMerge Docs uses values from this column as filenames for generated documents. Before documents can be generated, you must tell the add-on which header column contains those filename values. The generated documents will automatically use these values as their names.
Open Sheet Configuration.
Click Open next to Output Configuration.
Select Document Name from the navigation menu.
Choose a Document Name Column.
Save the Output Configuration.
Run the merge again.
This error usually occurs when:
Output Configuration has not been completed.
A Document Name Column has never been selected.
Output Configuration was cleared or reset.
The Document Name Column is one of the required Output Configuration settings. In addition, every row being processed must contain a filename value. Empty filename values are not allowed and will result in an error during document generation.
Choose meaningful and preferably unique document names. This makes generated documents easier to identify and organize in Google Drive™.