It's great that we now have a way to know the error message when something goes wrong in the conversion, but it's still difficult to then research what's the underlying cause or to obtain more information to help understand the context.
Please provide more details if possible:
The Attachment ID that was trying to be converted
The configuration options that were chosen
Did the error occur when creating ContentVersion or ContentDocumentLink?
User ID of the intended owner of the new file and their license type
It's great that we now have a way to know the error message when something goes wrong in the conversion, but it's still difficult to then research what's the underlying cause or to obtain more information to help understand the context.
Please provide more details if possible: