-This error can happen when scheduling a batch job using the mass document generating tool, batch mode.

How to resolve:
If you are testing the process one record at a time and the document is getting generated though when selecting mutliple records or doing mass document generation and it doesn’t work, then you know it is an issue with batch mode. You can try disabling batch mode and then re-enabling it which should refresh the scheduled batch job for you. Also make sure you have latest app package version (1.952 or later) installed from AppExchange.